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...
Always cut corners. Look for areas where you can do it but be careful not to drive off the edge of a table.
Don't drop an EMP blast when you don't have a clear run out of the group.
Fire a rocket only when you see a target ring before you.