Update: I was unfortunately not aware of Shamus Young's severe criticism of Fallout 3 available here to link in the original piece and I regret that. It dovetails rather nicely with what I've written and it's much better executed than my piece. I strongly recommend anyone...
Keep on the move just like you would playing a twin-stick shooter.
Smash as many crates as you can early on to find extra health.
It's worth grinding to get the cash for your evolutions, otherwise you'll end up stuck.