I sugget that you head over, open mindedly, to www.reapermini.com and check out The Craft.
Sure, this is a Gaming website, but frankly after reading eveything that Shep Paine wrote in his books, everything written in Finescale in the last twenty plus years, after reading European modeling magazines on the subject and working with oil paints for over twenty years on figures from 1/35 to 80MM scale, I have learned more by reading articles and the incredible figure painting forum there than anywhere. If Orks and Tyrannids arent particularly your thing, focus on the human skin painting articles. I find Bette Davis Eyes and Let It Flow to be particularly helpful and I have them printed in a 3 ring binder. The absolute key is working in LAYERS, thin, thin thin layers that build up a color depth. Most people try to slather on some paint in a thick coat and be done, but if you follow thier advice, it will pay off on ANY figure you paint. If you are using acrylics such as Vallejo (not Acryl) a drop of Liquitex Slo Dri added to your paint will increase the working time to where you can remove so much paint from your brush that you THINK it is all gone; that is the point where you will start adding your layers.
Vallejo has a site for thier paint series and there is an in-depth tutorial there, but I find the reaper site's paint tutorials to be easier to follow. Ignore the odd paint names, its just names for colors that you already have in your arsenal with new names added.
HTH and good luck, figure painting is now fun and I do quite a few of them now.
David
Build to please yourself, and don't worry about what others think!
TI 4019 Jolly Roger Squadron, 501st Legion