Checkout the forums at WoTs; they're loaded with good guides. I'm keen to get a better tank when I next get a chance ot play. I would say speed is very important in your little tank. Shell types I think are reasonably important ie HE is good as you don't need penetration but do a little less damage. Crews and their proficiency are important; I blame mine for me being rubbish.
Please share if you get any tips!
My German traktor is looking pretty good with a lvl3 engine and lvl2 suspension its quite nippy.
EDIT: My usename is the same as on here so feel free to add me. (I'm noot very good though!)