I've played over 1000 TT games.
There are 2 gameplay styles. I prefer number 1 it's more straightforward
- Bottom, Top, and a Jungler
- Bottom, Top, and a support who takes jungle camps.
3v3 is very snowbally. You always want to push your lane and you want your jungler to be aggessive. The best jungle path is to take wolves and then gank (you hit lvl 2 off 1 camp). Then go back to your jungle and finish off the remaining 2 camps (hit lvl 3) and take your alter.
The alters are not that important to have. But if you control both you get a movespeed advantage which is something to consider.
Vilemaw is very risky to do and should only be done when you have killed 2 players on the enemy team or have both inhibitors.
Keep your nexus turret alive because you can easily turtle under it and catch up if you are behind.
Meta champs are:
Early game Champs,
Fighters,
CC mages.
assassins don't really belong and ADC's only work if you have a strong support..But i don;t like that playstyle
http://www.nerfplz.com/2016/07/2016-champion-tier-list-ranked-3s.html
Link to a fairly accurate tier list.