I'm fairly new, but I'm learning pretty quickly, and in some cases providing quite a boon to my team. Generally, this is because I play Sedna, who I basically turn into a heal/regen bot and run around capping flags and securing lanes with my other team mates. I have learned to make due with very low hp for most of the game, and instead focus on speed items, allowing me to assist team mates as rapidly as possible.

In other words, when I play Sedna, I play her to cap flags and in the long run it generally works out.

When I play TB, the class I basically bought this game to play, my team loses. Inevitably.

I am the worst TB ever. Horrible does not come close to describe me, I think that throughout all the many games I've played I've managed to kill maybe once, and very very rarely do I outlevel the enemy as I am supposedly want to do.

I've read the guides for TB, seen the builds, etc. Trying them out hasn't really helped... I still suck. 

I need to understand the nuance. So if you think your an awesome TB, and you cause cold fear to run up your enemies spines, then please gimme the information I need, because right now I basically exist seemingly to feed.