what's the problem? if you need to make some big progress on it I say make some big shapes. create large shadow and highlight areas then add details after that.

start by making your outlines. get some form, some simple shapes. colouring comes after. if you're using a reference, please show us it. If not, use one.

Edited by Partack - 27 April 2012 at 8:05pm

That palette made me laugh, not so much the amount of colors than the way it's organised. I'd consider adding colors when you need them along the way...
But let us know why you need to finish that, how much time you have, what it is for, what it's supposed to look like, etc. any information so we can actually help.