So how I tend to work is I make a sketch, them some pretty sloppy lineart and color underneath that. I work towards realism and my lines are usually deleted at the end, thus they don't need to be pretty. When I first start I block in pretty basic places of highlighting and shading. After that I create another layer and refine things.
This is a silver bay i'm working on and it's still in the pretty early stages.
I draw a variety of animals, all of which you can find here:
BreakableHorseRider (Caitlyn) on deviantART
As I am always looking to grow as an artist I also welcome critique, don't worry about offending me, i've got my big girl panties on, I can take it. Of course I'm not looking fr "OMG your art sucks, yuck!" but anything that is helpful is welcome.