Welding upside down? Haven't tried that.
On vertical welds i use vertical up movements mainly. I'm still not the best at it. Horizontal i do backhand. I haven't had to do any overhead welds yet.
Have a read of these links. Should help you a little with the welds.
http://www.thefabricator.com/arcwelding/ArcWelding_Article.cfm?ID=1823
http://www.thefabricator.com/ArcWelding/ArcWelding_Article.cfm?ID=2139
http://www.esabna.com/EUWeb/MIG_handbook/592mig7_16.htm
(read this one til page 21.)