a few of my G&W mindgames:
Charge dsmash. Yeah, just charge it. For some reason people underestimate this move and they end up running into a fully-charged dsmash lol. If they catch on and wait for the dsmash to end, then immediately dtilt after the dsmash ends. They will already be running at you and get hit by the dtilt. I've gotten plenty of kills doing both of these things.
Run off the stage, then jump backwards and bair them. I do this a lot. Nothing too special, but still a bit of a mindgame. Good spacing move, too.
Short hop towards them, waveland backwards. Throws people off a bit. Switch it up and actually hit them with a fair sometimes.
Empty short hop fastfalls. Makes opponent a bit antsy and don't know when you're actually gonna hit them. Mix this up with the short hop wavelands and you're pretty hot stuff.
All of G&W's throws are mindgames. Since they all have the same exact animation your opponent has no idea where the hell you're about to throw them. Take advantage of this. Mess with their heads a bit. Do a bunch of the same throw for a while and then switch it up and capitalize. They probably think they're DI'ing wrong or something when they DI left but you bthrow them to the right
I know I might spam this match but the end is an excellent mindgame
http://youtube.com/watch?v=9RLb3FQaOws
that's all I can think of for now. have fun mindgaming!