Right now your team looks pretty decent (I'm not too sure about Ttar though, I really think it should go mixed). So your next step is to examine 'mon that is dangerous to you. Also, your battling style might need work. Predictions and whatnot. Practice more on battle spot.
Figure out what your weaknesses are exactly. List every single one of them and then figure out what you can mitigate. Look for which of your team isn't pulling its weight and see if you can't replace it with something else that'll help with consistency. Look for what is destroying your team and figure out what to change around to make it less destructive.
Seriously, battling with a bad team with a decent battle style will land you with a pretty lousy win/loss rate. Battling with a good team while using the same exact bad battling style will do the same thing.