Hey, glad to see you decided to give TF2 a try. And don't worry about changing Divisions bud. Insurgency's still my primary Division, even though I play TF2 quite a bit. We're just happy to have you on the TF2 servers when you decide to log them

. As for tips for playing...that's a hard topic, as there really aren't any specific tips I could provide. It's all really just based on play-style.
For instance: I spend a good portion of my time playing Demonman (favorite class, currently...used to be Pyro). What I like to do is ricochet a few regular grenades around corners to weaken anything that might be awaiting me (usually in enemy bases or around capture points). At this point, I usually switch to my 2nd weapon slot (the remote detonated sticky grenade), and move into close quarters with my foe(s). It takes a little skill, but these little buggers can be devastating if you know how to time your explosions while the grenade is still in mid-air, around a group of opponents. Another tactic (although defensive, instead of offensive) is to lace a doorway with Sticky grenades. You can 8 planted at any given time. I like to lace both sides of a doorway/vent shaft/window with a roughly equal amount. Now, just take some cover (make sure to keep line of sight on your grenade zone, so that you can see incoming foes) and wait for some poor sap to walk into your deathtrap. I usually keep my weapon on weapon selection 1 when I use this tactic, just to fire a few grenades into the hapless foe(s), in case the initial blast doesn't take everyone out.
Hope that helps, wish I could provide some more tips. Another useful strategy is to watch some gameplay footage on YouTube, and see what tactics other players use...or just try everyone out, until you get a feel for each class!
