don't overestimate your enemies / hp . you might think you have enough hp but who knows what burst damage / skills they would have . you could test them by going near them . if they retreat, you'd know they're weak and would not want to go into combat with you but if they start attacking, run . 1) either they're noob and only know how to attack or 2) they know they can kill you . and worst to the worst, time your orb of defiance to negate as much damage as possible . 

oh and, stacking health would surely help . 

What build are you using depends on the tips we give you.  So what is it?

Are you dying alot when you are changing forms?

Start off with rain of ice, stun them, change forms ring of fire, fireball and then chase them down.

TB only works when your team knows what they're doing.

If your team is running around clueless you won't be able to do anthing either, since you'll easily die in a fight.

On the other hand, you HAVE to stack speed, stacking health won't work on TB, it'll give you a second or two more, but you'll die just as much as without the extra health.

Speed allows you to get out of the fight when you're taking too much damage. I play pure fire TB so my speed is 8.4 with fire aura maxxed, yours will be less, but you'll decrease the enemies speed too, the total effect will still be slightly less though.

I always use Anklet and Boots of Speed, they work!

Ofcourse you need health too, just don't pick health over speed, speed will save you more than health.

Also, stay away from stuns / slows! If there's an oak / ereb near you, you know you won't be able to get out if they slow you, so be prepared!

If there's a Beast don't let him get within grasp range.

This is where you need your team, if the enemy chases you your team gets free hits in, once the enemy stops chasing you you turn around and start attacking from far enough away!

When you get that 1750 gold and are thinking about what you should get, a vlemish / plenor or hauberk of life, look at how the game is going so far.

If you're constantly taking a lot of damage go for the hauberk.

If you're constantly running out of mana go for the vlemish / plenor.

Hmm... Deep freeze I on lvl 14?

I think you should take it much earlier, for interrupts.

The beauty about BotS is that you can replace all mana items with health or speed item, that's what makes a great fire torchbearer with higher surviability. BotF is only superior in early game, after that BotS simply outclasses it in every way. A fire TB has a great speed synergy (as he gets +15% with 3 invested skill points), in addition the team and creep boost given by the Fire Aura is impressive.

You can still get Unbreakable Boots, they give both good mana and health. For the 2 other mana items you don't require (and you need those with any other Tb favor, especially with Renewal) you can get 2 more items with speed or health, which will make up for the BotF you don't have.

I suggest playing the Fire Torchbearer as offensive as possible, without getting killed, because he recks havoc on towers and in team ganks. Therefore using his talent fully to put pressure on the enemy team. He is also fast and therefore a great flag capper. Once he can chase, this build will become very popular. If you have form switched before a chase, you will even get am AA damage boost, more easily then any other dg!