Twenty years ago, an opinion writer for The New York Times described Colombia as a country dominated by “drug killings, paramilitary massacres, guerrilla kidnappings, death squad murders and street crime.”

Five years before that, a 1994 Washington Post article grappled with the question of whether people would want to visit war-torn Croatia. “Only the more intrepid will consider a trip,” the article stated.

And a New Yorker article the same year described the genocide in Rwanda as being so dangerous that foreigners providing aid never went beyond the airport perimeter. One street was described as a place “where everything is shot up and every building is riddled.”

In the years since, conflict and strife have receded, with infrastructure rebuilt and economies recovering. And through a combination of marketing, social media and development — and with the fading associations of discord that come with the passage of time — these three countries are now booming tourist destinations, topping travel rankings, bucket lists and flooding Instagram feeds.

More than 3 million visitors went to Colombia in 2017, a 200 percent increase from 2006, and the country has been ranked as a leading destination on dozens of travel lists, including the 2018 52 Places to Go list. Hilton Hotels plans to open three properties there by 2020.

In 2018, nearly 560,000 Americans visited Croatia, up from about 41,000 in 1998. Overall, 19.7 million tourists visited the country in 2018, compared with about 1.5 million in 1995.

“Nowadays, Croatia is one of the top destinations in the Mediterranean,” said Kristjan Stanicic, director of the Croatian National Tourist Board. “Our competitors are Spain, Italy, France, Greece and that hasn’t always been the story. People know now that we have great beaches and other things to do.”

And in Rwanda, tourism was up to 1.5 million visitors in 2017 from 826,000 in 2007, with tourists attracted to the country’s lush rain forests, the growing art scene in its capital, Kigali, and its gorilla conservation efforts.

Based on these successes, travel experts offer a playbook for countries looking to remake their image.

1. You can’t run from the past

Despite having one of the fastest-growing economies in Africa and often cited as one of the most impressive cases of post-conflict recovery, Rwanda is widely known for one horrific event, said Sunny Ntayombya, the marketing and communications manager for the Rwanda Development Board. That event, of course, is the 1994 genocide, in which 800,000 people, mostly ethnic Tutsis, were killed by the majority Hutus in 100 days.

“Throw in the fact that there’s only been one major Hollywood movie about Rwanda, which fuels the negative perception of this small African country that’s kind of unknown already, so even if you know a little about Rwanda it’s probably in the prism of ‘Hotel Rwanda,’” Mr. Ntayombya said.

“The way we’ve tackled that is not by running away from our past, but rather by telling the world that Rwanda is not just one thing, not one event, not one series of events — it’s a story of the depths of humanity, if people work together and are disciplined,” Mr. Ntayombya said.

Although Colombia’s conflict was vastly different from Rwanda’s, the idea that drugs were everywhere and that a Communist insurgency also stoked violence have been fueled by popular shows like Netflix’s “Narcos” and the Colombian telenovela “Pablo Escobar, The Drug Lord.” Much like in Rwanda, those charged with promoting the country could not ignore the past.

“We didn’t want to hide away from the fact that, yes, there was violence in the country and a guy like Pablo Escobar is associated with the country,” said Julian Guerrero, vice minister of tourism for Colombia. Until this summer, Mr. Guerrero was vice president of ProColombia, a government agency in charge of promoting Colombian exports, international tourism and foreign investment to Colombia.

Rwanda and Colombia’s success might be instructive for the Dominican Republic, where the deaths of at least nine Americans caught the attention of the international media and resulted in a decline in tourism earlier this year. Foreign arrivals fell 11 percent and 7 percent in July and August compared to those months the previous year.

Specialists in crisis management said that the country mishandled the news from the beginning, arguing that the deaths were not statistically unusual and there was no cause for alarm, rather than getting ahead of the narrative. “From the onset Dominican officials have had a defensive response,” said Beck Bamberger, chief executive of BAM Communications, a public relations firm that deals with crisis management. “That response doesn’t instill any trust for travelers.”

The F.B.I. announced last month that three of the deaths were the result of natural causes.

2. But you might be able to use it in a catchy marketing campaign

Colombia began its rebranding efforts in 2008 with a series of videos that showcased the country’s beaches, jungles, cities and mountains. Each video included the phrase “el riesgo es que te quieras quedar” — “the risk is that you’ll want to stay” — a play on the country’s image as a haven of drugs and violence.

“We’re not hiding away from the fact that Colombia has problems, but we want to tell the good news, too,” Mr. Guerrero said.

3. Bring in the planes

Croatia was not only scarred by ethnic conflicts of the 1990s, but also had the lingering effects of being part of postwar socialist Yugoslavia, which didn’t encourage tourism. From most major cities, getting to Croatia required flying to Italy, Hungary or Austria and then taking a bus, train or ferry.

“We had to improve a lot of the flight connections,” Mr. Stanicic said. “We now have flight connections with main European hubs like Frankfurt, Amsterdam, Munich, London.”

In 2013, the low-cost carrier Ryanair made the airport in Zadar, a city on Croatia’s Dalmatian coast, a base, and in 2017 Aer Lingus, the Irish carrier, began service to Split. This year, Alitalia operated seasonal Rome-Dubrovnik and Rome-Split services.

After seeing an increased interest in visiting Croatia from people in the United States, China, India and Australia, Mr. Stanicic said, there has been a concerted effort to work with airlines from those countries.

This year, American Airlines introduced the first direct flight from the United States in 28 years, on a seasonal route three times a week from Philadelphia to Dubrovnik. The last American carrier offering nonstops to Croatia was Pan Am, which ended its service in 1991.

4. Find a symbol

“We don’t have the pyramids or the Eiffel Tower or Machu Picchu,” Mr. Guerrero of ProColombia said. “And for certain markets it is important to identify an icon, so we said what could that be?”

The answer: birds. The country is home to nearly 2,000 bird species, the most of any country in the world. In a 2018 marketing campaign that included sponsored press trips to Colombia, journalists last year were not only shown the diverse types of birds in the country, but ways for travelers to connect with nature. The campaign took some time to gain traction, but soon flattering articles with headlines like “No longer ruled by drug cartels, the wild West of Colombia is a bird-watching paradise reborn” and “Can bird watching help save Colombia’s forests?” began popping up.

In Rwanda, the tourism board did a big push around gorillas and gorilla protection. The country uses social media to promote the opportunity to spend time with gorillas and sells tickets to the annual Kwita Izina, a Rwandan ceremony of giving a name to a newborn baby gorilla.

The lesson is clear for Memunatu Pratt, the minister of tourism and culture for Sierra Leone, which suffered a deadly outbreak of Ebola in 2014 that caused tourism to plummet by half from the previous year. Five years on, it is yet to make a significant rebound. “We are trying to look at Rwanda and how it has used the gorilla as the national animal,” she said. Her country’s choice: chimps. “We are using the chimpanzee as a national animal and it gives us an opportunity to consolidate and conserve, and a lot of tourists care about conservation.”

5. Keep up the marketing campaign

Colombia, after a glancing mention of its difficult history in a promotional campaign in 2008, built another one around its own literary hero, the author Gabriel García Márquez. The most-watched video in that campaign has more than 3 million views.

“Most people know his name, most people know his books and he is, in a way, a celebrity,” said Mr. Guerrero. The most recent campaign, called “Colombia, feel the rhythm,” is based on the idea that Colombia is home to 1,000 rhythms.

“People want to feel connected to a place and we believe that music is a very powerful way to do that,” Mr. Guerrero said. “The world has not had the conversation about the relationship between music and travel like the way it did about gastronomy and travel years ago.”

Croatia, too, looked for a way to make tourists connect with the country. Ahead of the 2018 World Cup, Croatia’s tourism board created a video that took viewers across the country, through the eyes of its national team’s most popular soccer players. After the players emerged as stars of the Cup, the video made rounds on social media. It includes Luka Modrić inviting people to his hometown, Zadar, and Mario Mandzukic suggesting that people travel to Slavonia. The video got nearly a million views.

6. Don’t forget the influencers

In 2018, the Australian-American actress Portia de Rossi gave her wife, Ellen DeGeneres, an on-camera 60th-birthday gift: A trip to Africa culminating in a visit to a new campus named for Ms. DeGeneres to be built at The Dian Fossey Gorilla Fund in Kinigi, Rwanda. The fund continues the work of Fossey, the naturalist who made Rwanda’s gorillas her cause and who was murdered in 1985.

Since that gift was given, on live television, Ms. de Rossi has been to Kinigi to break ground for the campus (and shared videos and photos of the trip), and Ms. DeGeneres has visited Rwanda (and shared videos and photos from the trip). The couple has a combined 80 million followers on Instagram.

Last year, players for Arsenal, the English Premier League soccer team, began taking to the field in uniforms that said “Visit Rwanda” on the T-shirt sleeves. As part of the $39 million marketing campaign, Arsenal players will visit Rwanda and coach at soccer camps. The Rwandan government received backlash from people questioning the government’s financial priorities.

7. Get lucky

When HBO began filming “Game of Thrones” in Dubrovnik in southern Croatia, most Americans probably couldn’t pick out the sites that later became known as King’s Landing. But eight seasons and a contentious series finale later, the show’s fans are a “significant” part of the country’s tourism market, Mr. Stanicic said.

And now Dubrovnik is all but synonymous with the word “overtourism.”

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