I have super-fine straight hair that's roughly the strength and consistency of rabbit fur. It's disastrous without a strategy.
1- Trim your hair at a minimum of every 3 months to take off the frayed ends- it won't hurt length and you can actually grow it longer as it won't 'unravel' as badly, or break off from the ends.
2- Take a hair, nails, skin supplement...of course you won't notice a change in your hair for a year, because it will make a difference on the hair you're forming NOW, which is still in your scalp, but you'll notice in your nails soon, and it DOES make a difference in your hair for later.
3- Don't overwash. Folks with finer hair don't need to wash their hair twice, and you really only need to wash your hair where it meets the scalp, letting the suds and rinsing process remove what little oil, dirt and etc. remain on the lower hair shaft. Washing is very damaging and makes the 'scales' that form the shaft rough up like velcro rather than smoothed down like a snake's skin.
4- Use an anti-frizz product (oil-free or not) and an alcohol-free styling product from the ears down. After a shower, use a product that doesn't dry your hair- a little glob in your palm of each, rub hands together to distribute all over your hands, then smooth through your hair from ear-level and down. The act of combing out your wet hair will distribute it at a lesser concentration above that point, and that's perfect. You don't want a lot above that point.
5- Be gentle. Don't use force when combing or brushing out your hair. The act of stretching your hair during forceful brushing can damage the cuticle and leave it frayed and velcro-like, as well.
6- Use non-damaging hair ties and pins that won't do damage. The skinny hair-ties bind hair and make it weak. Use larger ties and plastic hair pins.