Recasting an iconic character is always a complicated process for a big franchise, but Solo: A Star Wars Story's Alden Ehrenreich was lucky in the sense that he had Harrison Ford to guide his take on the Corellian smuggler. In fact, one of the critical things that Ford did for his successor was walk him through his own experience as Han to convey the evolution of the character. Lucasfilm president Kathleen Kennedy opened up in a recent interview and explained:
What [Ford] did so beautifully for Alden was he talked a lot about what he remembered when he first read Star Wars, and what George had done with Han. Who the character was and the conversations he had for so many years with George about how that character developed. He gave Alden that kind of insight which was invaluable. There were several times in the course of making the movie where Alden would actually recount some of the things that Harrison had pointed out. I think that was really, really helpful to him.
Although Solo: A Star Wars Story is going to explore a new avenue of the Han Solo timeline (and hopefully not meet up with the events of A New Hope in the way that Rogue One did), it was still important for the actor to get a sense of Han as a character. In that regard, Alden Ehrenreich was lucky enough to get to meet Harrison Ford, and the previous Han Solo actor gave him insight into the earliest days of the character. This hopefully went a long way towards informing who Han becomes in the years between the beginning of the Star Wars franchise and his eventual death during the events of Star Wars: The Force Awakens.
One area in which that manifested itself while shooting was in Alden Ehrenreich's knack for channeling Han's ability to fake his way through situations in which he finds himself out of his depth. Ron Howard addressed this in his interview with EW and explained:
Han has survived and proven that he can survive, but he's never sure he's as quite as smart as he needs to be. Change that. He's not really 'smart.' That's not the word he used. Han's not as on top of it as he needs to be. So he wants to give the appearance of [control], but in fact, he's often scrambling. I think Harrison played that beautifully, and Alden and I talked about both of those ideas a lot.
That's something that the first trailer for Solo: A Star Wars Story has already shown us. Alden Ehrenreich's Han is cunning and capable when a situation calls for it, but several scenes also show him just barely scraping by on pure luck. Perfect examples of this are the opening chase in which he outruns authorities in a speeder, as well as the end of the trailer when he tries to calm down his companions in the cockpit of the Millennium Falcon. Luckily, Harrison Ford was there to help the new Han figure out the right way to navigate the role.