There are several easy methods that you can use to paint over stained wood. Some methods require you to sand or de-gloss the surface, while others use paint specially formulated for painting over varnish.
Painting over stained wood often take a few days, so it is essential that you have a set-up workspace. It is best not to move the wooden pieces around throughout the process.
Using dish soap to wash the wood removes any grease or dirt that has collected on the surface. Next fill any cracks or holes in the wood with some wood filler.
Use sandpaper that is between 150 and 220 grit. Sanding can take up to a couple of hours to but you can achieve the same result in around 15 minutes by using liquid sandpaper.