in terms of all over dye or highlights...

what have you used that's worked?
what have you used that's been disasterous?
have you dared to go blonde?

i've had the best luck with l'oreal feria hi-lift brown in cool brown. it doesn't lighten my hair even as close as the color on the box, but it's made it a noticabley lighter brown without being totally brassy.

i've had the worst luck with l'oreal preference true brunettes in ultra light natural brown. i swear to you, i followed the directions exactly and my roots turned orange and the rest of my hair was still nearly black. it was hideous.

people with dark brown/black hair should never attempt to lighten unless it's done by a professional. otherwise the results look brassy and orange and disgusting.

i've got naturally dark brown hair and in the past i've bleached it to platinum blonde and it has never been brassy. i used lorel perfect blonde & silver toner. & afterwards i used lots of john freida products to keep it feeling/looking nice. i'll see if i can find any photos

lorel perfect blonde

Well I have my hair dyed dark brown, and I wanted red in it and the hairdresser used 'magma' or something??? It's completely shit, it washed out the first time I used it and now looks so crap, don't use it.