Today I went about trying out a way to paint my Imperial Fleet for BFG / Rogue Trader in a way that would be both fast and good-looking. I used a model I had gotten off ebay, that I had to strip in simple green, so there was still lumps of paint in hard-to-reach areas. This made it kinda rough, and perfect for a test model! For your benefit, I broke down the steps while doing this...
STEP 1:Basecoat the model black. You can do the flying stand too, but in all actuality you will probably have to redo it.
Step 2:Drybrush a mixture of 50/50 Black and Light gray, or a pre-mixed dark gray if you have it, onto all but the prow. The actual colors are not important, as long as you drybrush from darker to lighter. After the dark gray, go over it again with a drybrush of the lighter gray. Again, don't hit the prow so that there isn't too much of a buildup of paint. NOTE: I used gray, but building up any color would work with this technique. Therefore, you could do green, blue, or any other color you desire by building up from dark to light. Just decide on the color you want to use, mix 50/50 black with it for the first coat, do a second coat in the unmixed color, and finish with a 3rd drybrush of 25/75 Bleached Bone mixed with the color (bleached bone being the 25).
Step 3:In this step, fill in the prow with the color of your choice. Red, Blue, or White are popular colors. If you get a bit over the prow lines, don't sweat it too much. The next step should take care of this issue.
Step 4:To paint the prow lines, start with Tin Bitz. While that is drying you can paint weapon barrels and the engines in Mithril Silver (or gunmetal, if you prefer a darker metallic). After that is done, you finish up with Shining Gold over the Tin Bitz. Alternatively, you could skip doing tin bitz and shining gold and just use silver, if that would match your colors better.

Step 5:
Lastly, we need a couple of washes to bring out the definition. I used Badab Black for the body, and for the prow I used Devlan Mud. You need to pick washes that best complement the colors you chose. For example, don't try putting Baal Red on a Blue prow, unless you WANT a purple prow. Be smart about it.

If you desire, you can finish up the flying stand at this point. I've seen people take an old toothbrush, dip it in white paint, and flick it at the base to get a starfield effect. Obviously, if you are going to do this, remove the model first so you don't spray white globs all over it. Also, I have seen people paint script for the vessel's name on the base. Furthermore, why not try a combination of the two? If you have an airbrush, it would be easy to go crazy with nebula effects and so forth. Just make sure, just like your regular 40k minis, that the bases of your fleet match to give it uniformity.
I hope you enjoyed this tutorial! I strongly urge people to look into BFG, as it is a great supplemental game to 40k.
Until next time,
--FP135