Your name in lights, perhaps. Your first award, maybe.
But when you have the director of the biggest film of the year - and maybe of all time - asking you to play a part in his movie, that is as good a sign as any.
Such was the case for three Indonesian actors who millions of people will see in Star Wars: The Force Awakens this weekend.
All three - Yayan Ruhian, Iko Uwais and Cecep Arif Rahman - starred in the widely-praised 2012 Indonesian action film The Raid, or its 2014 sequel.
And it was thanks to Star Wars director JJ Abrams' enthusiasm for the films that they got the call to take part. It was only in the past week that their appearances - as intergalactic smugglers - were confirmed.
(No major spoilers ahead!)
"I was just a fan. It was an opportunity," Abrams told the website Slashfilm. "I knew we needed people for this one sequence that would be particularly fun to see a group of people working together.
"I thought 'God, I wonder if the dudes from The Raid would be available?' And to my amazement, and they were willing, and they were incredible. They showed up and did a terrific job."
Their roles are not as substantial as Harrison Ford's, or the robot C3PO's for that matter, but they play important enough a part to justify having Lego figures made in their image.
Being on the Star Wars set presented challenges to the actors, said Rahman, who is also credited as a stunt choreographer.
"Our filming schedule fell during the month of Ramadan and the three of us were fasting," he told the Jakarta Globe newspaper.
"It was one of the toughest fasting months for me, because we couldn't eat and drink for almost 19 hours. But the crew always made sure to prepare food for us to break the fast and to make sure we got some time to rest."
Their casting has proven popular with fans in Indonesia. One wrote on Twitter: "Caucasian characters work for Star Wars, but we're proud to have you guys in there!"
Another Indonesian actor from The Raid 2, Joe Taslim, starred in the 2013 film Fast and Furious 6, and will appear in the next instalment of the Star Trek series next year.
The Raid films, directed by Welshman Gareth Evans, follow Uwais' character Rama, a Jakarta policeman, as he battles against the city's underworld.
The films were released to critical acclaim, with the first winning the audience award at the 2011 Toronto International Film Festival.
The Force Awakens opened across Indonesia on Friday, but Uwais, for one, might find it difficult to catch the reaction, as he is filming deep in the Indonesian jungle, and was unavailable for interview.
As for whether they will appear in the many Star Wars sequels and spin-offs to come, Ruhian told the Coconuts Jakarta website he had to stay quiet thanks to a non-disclosure agreement.
"One can only hope," he said. "For the last one, we had to be quiet about it for two years, let alone the next one."
As a film actor, there might be a few signs that you have made it into the big time.