Keep your ends trimmed. If you are thinking that your hair looks right, except for the ends that look dry or split, you need to get a regular trim. I know you want to have really long hair and the idea of cutting your hair sounds like keeping it from growing, but on the only run, trimming your ends periodically will actually help hair growth and health. This will also make your hair look and feel very healthy from root to tip. Another thing you can do to prevent split ends and avoid (or postpone) trimming is to moisture your hair regularly.
Keep coloring to a minimum. Hair dye is not good from your hair, especially if you use lot of them. I like to dye my hair and in order to keep the damage on my hair to a minimum I use semi-permanent hair dye, some this is something to think about before you decide to color your hair.
Avoid heating tools. I am not a big fan of blow-dryers, I use to wash my hair one hour before I go to sleep and air-dry my hair. For some reason, if I have to use blow dryers I use the cold setting. Less heath styling tools like flat iron or curling iron is better. These procedures can do a lot of damage to your hair. So, if you take out of your routine as much heat styling as you can, you are helping your hair a lot.