Shared Bluff

Ok now this works best in my opinion in shared bases games.
Basic Shared Rule: NEVER let the opponents see your bases.
1)Ok now usually 3v3 shared. Tob VS Bottom. You have a land bridge between your bases. Have someone stick 1-2 z's and block it. You play as toss. The most inportant thing in shared games is to not let them see what your doing. If they have to guess what to use againt you. They will most likely be wrong. Ok u should be toss. Have an ally be terran, Toss works too but terran are better. Have your other ally be toss.
Have your terran ally build a few fast turrets. in the edge along the entrance. This will most likely stop overlord scouting. Have the z's in the choke to block the 1 ling scout. Now all they now is that there is a toss and terran. If the terran makes a few marines and puts them in center instead of z's all thye know is a terran.
2)Now the fun begins. Build 12 gateways. 3 forges. 1-3 Templar archives. CCore(build that early as you can. so when oyu get gas you can build other stuff right away). get a Citidel, a Stargate, Fleet becon. And 2 Robotic Facilities. A observatory. And you can get a reaver bay if ya want. I know thats all the building but they put them in the game for a reason.
3) Build High Temps, As many as yu can, Then build about 3 arbitors as you go. You should have built observers as soon as you could to scout. Scouting is VERY important in all games.
4) Upgrade Holucinate, Storm, All ground aboilities at forge, and all observer and arbitor abilities.
5) have your terran ally go mass bc's. Wraiths works but bc's better. If hes toss carriers work but not as good.
6) Have ALL of your high temps Holucinate a BC. With all of them you can get an army 8 Times the size of your allies.
7) Morph to archons.
8) You and Your ally attack the center d(usually weekest againt air sadly)
9) Have your archons Attack too. Most players seeing That many BC's attacking will assume you mc's and built with another race. They will usually leave as they see it come into there base. Usually get at least one person every time. Your Fake BC's will be taking the hits of the defene while your terran ally destroys pylons and your archons crash through. Have your arbitors stasis there units.
10) If one of them is zerg build 6 arbitors. Cause youll need them.
11) If you have a chance sneek a arbitor into there base and recall about 2 bc's and 6 dt into there base. They will usually bring anti air to kill bc. The dt will still kill Gatherers and maybe nexus.
12) This works 90% of the time. Usually more.
13) Make sure you attack the guy that built there Ground Defence. He will most likely leave. And usually accuse you of hacking(unit hack?).
14) Your other ally, Whatever race he is an do about anything. Usually i have him do defence.

OTHER
15) If your other ally is toss have him do the same thing. WIth both of you Holucinating mass bc's they will run scared.
16) If one of them is zerg have 2 arbitors go to where they kept there Overlords and stasis them. Unit levels drop. Stasis again with the other one when they undo. A zerg best atribute is there ability to rebuild fast. Without suply there very weak.
17) there is an alternitive version of this. Do NOT morph to archons. keep the high temps.Holucinate your allies bc's and the other guys main units. If the other guy is zerg have him Build a Muta or gaurdian. Only one if hes going ground. Holucinate it and attack with the ground. Although you wont get much fighting its really good because you will be there backup. even though there not real. Have your allies constanly building units. Holucinate them when there baout to attack.
18) Sooner or later they will most likely get what your doing. Then morph and attack.
RULES
1) This is basic. TEAM WORK WOrKES BETTER THAN EACH OF YOU DOING YOUR OWN THING.
2) Haveing one guy just doing defence, Another doing a distraction or Min attack strat and the other doing unit kill works well.
Example: Have one toss player build cannon d and high temps with storm(best d), You get Dt's Shuttle, And arbitors(observers too, Duh), An your other guy Get him main units. The d gy will cover the base. The main unit guy should attack there units. usually haveing a few arbitors with him to stasis half there forces will help him a lot. While one guy attacks there units you drop the dts into there bases. Take out gatherers first. Dont Worrry about actually destroying the building unless they are zerg(they rebuild drones too fast) then attack suply depot/pylon/ and stasis there overlords. Bring a few corsairs to finish off overlords. Now this works really well if you do it right. Finish off nexus and cc's after most of there suply is dead. Make sure you finish off all scv's and probes first. You wont be able to kill alll drones and hatches really fast cause most zergers build about 12-24 hatches. Go for suouply. They wont be able to rebuild and they wont have mns. they will have to keep rebuilding ol for supy but just stasis and kill as fast as you can. If ya wanna do your attacking ally a favor kill ydra den and spire so he cant be attacked. spore colonies too. but go for suply over all.
Ok i know this dragged on a bit but it works incredibly well. Actually If everyone does there part and isnt a compleat newb you will win.