I'd recommend going through the codex and doing a google image search for Dark Eldar models, saving some pictures/examples of schemes that you like, then bringing those back as examples for people to advise you on.
Other good sources of cool colour schemes:
Google image search Insects, spiders, tree frogs, salamanders, lizards, snakes, birds of paradise
As Alino said, you need to decide how you want your Dark Eldar to be portrayed. Do you want them scary and dark? Do you want them vivid and colourful? It's very easy for one of us to say "PAINT THEM YELLOW!" but do you really want yellow dark eldar?
The beauty of DE is that their forces are made up of subforces from the Kabals, the Covens, and the Cults (wyches). You can paint all these different factions in the same colours, or you can mix it up and have each faction have a defined colour scheme. The second option gives you the chance to play with different schemes within your force, or to introduce some contrast into your own army, where one part can be brighter or darker.
| ||Modern Synthesist - See all of my nightmare creations|
Haemonculus Coven - See my Coven units
Tyranids - See my Niddy conversions