In timed FFAs, you have to be quick and have a sharp eye out for damage and stuff. If you see an opponent start flying towards off stage, chances are that opponent is only concentrating on two thngs: getting back to the stage and the opponent that knocked him/her off in the first place. That way, you can go out and gimp that opponent right quick, stealing that kill.
In stock FFA, you're goal is simple, run around, don't get hit, cause 1v1v1 while you stand somewhere saying "You're Too Slow!" then watch as the three people try to attack, so you run away, and the 1v1v1 continues. Then you take out whoever survived that.
LuLz: if a FFA goes down to you and one person, and one person has 1 life while you have like 3, sandbag. At least until the last stock, where they'll have like 192% damage because you didn't use any KO moves, and profit.
I have too much fun with FFAs.