setting up screen
This is pretty much the first thing I do. I've learned the hard way that I really really need persistent terminal state.
One of the changes I always make is to switch the default key combination away from C-a. Initially I did this during my "year of trying Emacs" (since it's the default "move to beginning of line" shortcut). I chose C-z (via escape ^Zz) but you might want to do this anyway if for example you feel C-b would be easier to type.
The other must-have is labels for the tabs. I want to know what I'm switching between (a suitable modification to hardstatus).
The status line looks something like this.
It's pretty minimal; you can add an arbitrary amount of customization to your status line, but this is all that I need.
Finally, there are a couple of "features" that have to be disabled: the screen flash on tab completion (vbell off), and the annoying startup message (startup_message off).
I'm sure you know all about switching tabs, detaching and resuming sessions and all that. The only (in hindsight obvious) rule of thumb I've learnt is to always launch a session with a name. Because you might just want to start two sessions. And then when it comes time to resume them, you won't know which is which. So make screen -S <sessionname> your friend.
Anyway I have a github repo for my "dotfiles" and you can see my basic screenrc here