For a good starting-place, I'd suggest a visit to where David goes to get inspired sometimes:
Arne's spaceship guide; it's one of the best fundamental discussions of form and its role in aesthetics in game art.
See the various tutorials around here for some practical tips on fast workflows; I did one about how to speed-paint from a loose sketch, which you might find handy, because it can work well with brushy styles, although I didn't really talk about that much at the time. Someday I need to talk about detailing and pixel-art concepts, too.
msShadowy's released some great guides / videos and his workflow / styler is somewhat similar to yours.
But don't be too scared to give it a go. Ships are mainly about building up forms in grays from sketch and then working in color; there are a lot of ways to approach that. I've largely ended up drifting to 3D because of my time constraints, but there is no real "right answer" to get to a good approach; there are a lot of ways to build up nice sprites.