Against Generals, I usually engage them in Frost.  I start out with a Rain of Ice to cut out whatever I can (priest minions, creeps, etc.).  Then I immediately pop into Fire and unload all I have.  By now, they're below half health, although I'm out of spells to sling for the moment.  Many will turn tail and run when they see their health bar going down that quickly, but most Oaks and Sednas will charge in.  Usually, all you can do is go Frost and let Permafrost slow 'em down or (if you have it, my build doesn't) Frostnova, then retreat.  If you're by a flag, try to lock it real fast before your swift exit.

Well those don't really address my early game issues, but Parasitie Egg is worth a try late game.

So pretty much just stay out of their lane completely? Like I said I tried to play conservitive but they were doing a good job of chasing me away.

If you're playing against Sedna always use frost, fire build TB's bring a smile to my face when I'm playing Sedna, as heal will negate fireball quite happily and I can generally interrupt nova with pounce. Circle of fire doesn't do enough damage since passive regen on Sedna is generally pretty high.

On the other hand, by using deep freeze/rain of ice/ ice nova you can stop Sedna from healing, freeze the pesky priest minions and also slow her so she can't run after she takes that handy shatter dmaage.. Rain and freeze dont have large cast times so she won't be able to interrupt very often.

Health stacking will also piss a Sedna player off, since they have very low dmg apart from pounce, and if they spam that early in combat they are liable to get beaten up since they used their cheap interrupt.

don't rely on frost nova too much, because restorative scroll will turn you inside out.

People actually use those? I was under the impression they didn't, since it didn't work on Demigods.

I find that when playing TB that you just have to put up with little flag control for the first few levels. In the beginning you don't have enough mana or spells to effectively push out some DGs. I find that the only a few specs can fully drive me from a lane though. Most of the time I just hang back, and then dart forward to AoE the creep wave, and try to aim it to also hit any nearby DG's/minions/towers if I can. I try to avoid going toe-to-toe though, and start running early and often until they turn back and I can then go back to harassing them.

Later on, Rain of Ice + Fire Nova shreds through minions like no one's business. While starting as a great farmer, and a good auto-attacker (be sure to switch forms for the boost.), part of playing TB is accepting that you don't really come into your own until the beginning of the mid-game. Until then just dance around the generals, get pot-shots in if you can, and focus on the creeps.