MISTAKE 3 - USING COUPONS ON ITEMS THAT ARE FULL PRICED
Coupons are supposed to make things you intend to buy, a bit cheaper and help you save some money. That being said, it is better to use your coupons on those items that are already on sale, rather than full-priced ones. Using coupons on items that are on sale will make you get them at a negligible cost. They almost become free. As much as possible, avoid using coupons on full priced items.
MISTAKE 4 - USING EVERY COUPON YOU FIND
You don't need to use just any coupon you find because not all of them represent actual savings. You should only use coupons that save you good money on things that you actually need. Rather than picking up any coupon you come across, make sure it is one that is of some use to you. It is unwise to use coupons on things just because you can get a discount out of them, and end up missing out on good deals when they arrive.
Wisdom in use of coupons can really help you save some real money.