Here are some habits of mine you may want to take into account:
I straighten/heat style my hair a few times a week. I use a heat protectant religiously.
I am currently using garnier triple nutrition shampoo/ conditioner, but will use head and shoulders about once a week for a deeper cleanse.
I deep condition my hair with pantene's beautiful lengths restore treatment.
I never brush my hair when it's wet. I use a wide-toothed comb instead. Other than that I only brush it up to twice a day.
My hair is trimmed from every 6-12 weeks (I realize it's a big range... but yeah :P )
Other than the heat protectant, I rarely use any other styling products in my hair.
So, if you have any advice, please let me know!