Please help me suck less in the T30

Ectar:   It's an out and out support tank.  Your gun is your strength and you should be behind other tanks.  Going hulldown is effective but again you really want to be in a situation where there is other tanks in your team are in front of you.  Some TD's can get away with sitting in a bush but for the T30 you really want hard cover you can retreat behind. You have the advantage over other TD's at that level with your turret so make the most of it.  Many tier X TD's don't have clearance to shoot over things.  It can be a misleading tank to play as people try to play it like a heavy with big alpha damage, but the problem is that it doesn't have heavy armour.  Try looking for some high damage replays on Worreplays. I find that can sometimes be helpful - http://wotreplays.com/site/index/tank/377/version/30/sort/inflicted_damage.desc/    

Ectar:   No one should say you don't know how to play tie 9 TD's, but these 2 tanks have totally different play styles from the T30 as both tanks have strong frontal armour and can trade shots.