The basic tips:
1. Try to buy only items that are on sale (especially for things you really need but don't have Qs for).
2. As above, match your coupons with sale items to get the best deal possible.
3. Try to find a store that doubles Qs...that's how a lot of people get those huge savings percentages
I know a lot of times these stores are the more expensive shelf price stores, but with the double Qs, you'll find much better deals than elsewhere.
4. Stock up when you do find great deals, that way you won't have to buy those items again until sale time. (Buying more than one paper is key)
5. Don't expect to save 80% everytime...this is rare. 30-40% is a good savings. I personally always try to shoot for 50%. Set goals and move up as you get better
Good luck, and we're always here to help and answer questions!!