Not a mtn biker, but I have hills... LOTS of hills... and I have trouble with them too. Just try different things and see what works best!

I'm still befuzzled by gears and find myself completely wiped because I'm in the WRONG gear. I (finally) think I have my shifting issues fixed as I couldn't go down into my smallest gear and would just laugh and mock me. I rode five miles of REALLY hilly trail thinking I would be OK, but by the time we finished I wanted to slap DH (who looked fairly fresh) who's idea it was do THIS ride knowing I was having issues with the derailleur.

Good luck!!
Shannon