Masks, masks, masks...
Use olive oil on the lenghts (I mean, everywhere except your scalp), and keep your hair at least one hour in a warm, wet towel. Then rinse and wash your hair.
It's even better if you can let it on your hair the whole night, but protect your pillow carefully :-) I don't do this very often because I simply hate the smell of olive oil :-(
It also works well with Palm Oil, or Castor Oil, but of course it's more expensive!
You can also help the oil get into your skin by using a warm hairdyer on it. t won't dry the oil, but the warmth will help it get into the hair :-)
Also, when you make a classical hair mask in your shower, use hot water before in order to open the hair's shells (? scales?), make your mask, and rinse it only with cold water (so that the good things stay in your hair).
Also, when you do a shampoo, you should always rinse it quite long, until your hair "rustles" (?crunches? screeches?) when you move it. It is the sign that shows that your hair has been rinsed well (it can take quite a long time).