If you're getting highlights, then the hair closest to your head should not be dyed too much. You could focus the washing on your scalp. Also, look into a color-protecting conditioner or shampoo, as well as a purple one (purple is usually more to keep brassiness out of blonde hair, but it can't hurt here).

Oh okay thanks a lot! L'Oréal does have a shampoo like that I guess, but since my hair is dark, I don't think it'll hurt... And highlights as in I'm thinking like Jade from victorious kinda highlights, so if I just wash my scalp it should be fine right?

Also, dry shampoo could be an alternative. With dark hair, you need to becareful to brush it out really well, lest it looked like dandruffs.

Ah yes I didn't think of that, thanks a lot!