There are lots of tutorials around that are probably better than mine, but this is how I did it.
ROTJ
1) Clean up all flash, bubbles and/or imperfections
2) Assemble all parts with JB Weld.
3) Paint entire prop with flat black
4) Dry brush silver paint over entire prop
5) Dry brush Rust color over entire prop
6) seal with a satin finish clear coat.
ESB
1a) For butstock follow the wood grain tutorial at
http://sci-fire.com
1b) brush a small amount of orange onto the square greeblie
2) Paint the rest with flat black
3) paint flash tube with chrome spray paint (won't look like real chrome but close enough)
4) drybrush some silver/gray as you see fit over entire thing
4) drybrush some black over the chromed flash tube.