This is a tricky one to me. My hair is kinky (I've pretty much given up typing it beyond the number 4) and it swings when it's healthy.
I don't straighten very often, but when I have done it, my family has pretty much reached the consensus that it's never straight straight. My sister says quote, "it's straight for YOU." So if your main point is flat ironing, I'd say just use a good heat protectant like IC or Silk Effects or some of the other decent ones out there and don't put the iron too high. You shouldn't smell like burning hair when you're done.
If your point is getting it bouncy, straight or not straight, I'd say make sure to avoid product build-up, use a LIGHT leave-in, and maybe add a little fatty oil to your conditioner. Beyond keeping it health overall, that should about cover it. HTH!