Be humble!
As a consultant who has something to prove, it's easy to fall into the trap of overconfidence. I must admit that presenting myself as more than I was in my earlier days worked well. The "fake it till you make it" mindset got me far when I was a newer software engineer and again when I first started as a hands-on consultant. What I learned, though, is that you don't have to know it all. Even more than that, clients (and teammates in general) hate a know-it-all.
People aren't looking for someone who has an answer for everything. In my experience, others actually appreciate someone who readily admits where their expertise ends. How is this possible? Don't clients pay for the best and expect exactly that? Well easy, they will gladly pay for someone who has gaps in their knowledge if that person is honest, hungry, and hardworking. More than that, they want someone who can work well with others to actually deliver!
Being humble isn't about being unconfident in what you know. We're all still expected to be strong willed. We should use our experience and actual expertise to ensure things are done well. Otherwise, what good is being the expert in your field if nobody supports and follows you when you actually know what you're talking about?
For me, being humble means I'm open to the fact that I might or might not have the best solution for any given problem. If I am right, I want all the support I can get to implement my ideas. If I'm wrong, I want others to feel like they can step in and try it their way.
In the end, delivering high quality software takes a team. Alienating your teammates, by always trying to prove you know better than everyone else, is not a recipe for success. At least not in my humble opinion 😉!