Here’s a tutorial on speedpainting miniatures without losing quality.
Painting
Painting With Enamels
Olicanalad has a blog post with a photo tutorial on painting with enamels.
Painting Checked Patterns Tip
Iron Mitten has a tip on painting checked patterns on your miniatures. He uses it on Celt Cavalry, but there are innumerable periods that could use this tip.
Speed Painting To Tabletop Standards
This video gives tips on speed painting with the goal of getting them onto the tabletop, and not winning painting competitions.
Using A Wet Palette
Two good videos on using a wet palette for painting.