Tangled hair

I have a problem with my hair often getting easily tangled and stringy. My hair is long (mid-back), straight as a ruler and very fine. It is cut into long layers. I do a permanent color every four weeks, at the roots. Even after brushing, I find that within a half hour the length of my hair become tangled and stringy, not maintaining any fullness.

I see women with straight, moderately thin hair whose hair hands neat and straight, and never appears tangled.

Is there something I can do or use to get my hair smooth and shiny, and remain *mostly* untangled during the day? Or is it just that I`m born with it?

have you considered not having layers, layers contribute to tangles.

Yes, I have definitely used the leave-in conditioners. The advice on the long layers seems to be universal; I ahve subsequently found more comments saying the same thing. I guess its time to grow them out to one line. Thanks, everyone!