Well, I'm going to cheat. Be somewhere between "mediocre and good" at many things, and be really good at one or two things. If you can be great at one or two t

Well, I'm going to cheat. Be somewhere between "mediocre and good" at many things, and be really good at one or two things. If you can be great at one or two things, that is nice, but not strictly necessary. There's a lot to be said for generalists, or "T-shaped" people. Every single project requires a large breadth of skills all up and down the stack... and a lot of moving pieces (client, server, markup, JS, CSS, blah blah blah) that work together. There is a place for specialists, too. In fact, we need them to make the world go 'round. But... there aren't as many of those places. Here's a real-world example. I literally just finished troubleshooting this issue. Finding the bug and developing a fix involved (1) our iOS client (2) our React web client (3) our server-side auth, implemented in Rails (4) a messaging library with both client and server components (5) some other bullshit I can't even remember at this point. I'm not the best at any of those things. I'm barely even good at them. Honestly, I don't even fully understand the auth fix that our brilliant (and I don't mean that sarcastically) programmer implemented. But I understood enough of those moving pieces to isolate the problem and get things into his hands. It'd be really fucking great if I was the world's leading iOS developer or whatever, but if that's all I knew, this issue wouldn't have been fixed.