As ashlyndmarie said - chop off your damaged ends.
Also baby your hair. You have to nurture it to get it healthy. As someone who spend nearly a decade getting my hair chemically straightened and using straightening irons on it practically every day, I know how hard it is to recover from the damage and get the curls back!
I found the following helped me SO much:
No heat (if you must blow-dry use a diffuser on the 'cool' setting).
No combs or brushes - only finger detangling.
Deep condition once per week.
Pre-poo with coconut oil.
Get rid of my sulfate-laden shampoos and use moisturising, non-stripping ones with great ingredients (the one in my signature is a godsend).
Use a really good conditioner (again, the one in my signature).
Cut out hair sprays (SO drying).
Do gradual chops, often, to get rid of all my damaged ends and avoid breakage.
Since doing all of that my hair is in such good health and I have basically no breakage or anything