Besides organization, one of key rules to couponing is to know your prices. Over time, you will become more aware of what is considered to be a "good" price for the items you normally buy. Some websites encourage you to make a list of your most used items and go to your local grocery store and write down the price. Personally, I don't have time for that. I have found over time, you begin to learn what each store normally charges and what is considered a "good deal". In the meantime use websites like coupon mom to help you get familiar with each stores normal pricing.
In order to take full advantage of your stores sales, and good buys, you need to remember this rule..you buy when the item is on sale, not necessarily when you need it. This took me a while to become adjusted to, but I have learned this is key. One caveat to this rule is, do not "over buy" perishables and items that do not have a long shelf life. For example, a mayonnaise based salad dressing will not have a very long shelf life. Even if you purchase this item for .25, if you end up having to throw it away because you haven't used it before the expiration date, it's not a good deal. So you need to know what you need and what you have and watch your sales ads for sales.
For the beginner, I would recommend couponmom.com. Each week, she has grocery deals listed by state. You can use the pull down menu to find your local store. She will list everything in that weeks sales ad, if there is a coupon for that item and where the coupon can found, what the final price is and the percentage of savings. You can even create your grocery list and print it out from there.
There are many other useful websites similar to couponmom, but this is where I would start if you are a beginner. Once you are comfortable with couponing, you can branch out to other sites. My goal here is to help you get started, not scare you off. Yes, there are people out there who spend many hours trying to find the best deal, but most of us do not have that kind of time. I have found that over time the process becomes faster and easier, and basically only needs as much time as you want to commit to it. Any amount of money you save is $$ in your pocket, right?
After printing your grocery list, match up your coupons and your ready to go. While shopping in the store, I like to open my binder and keep it on top of the carts handle/seat. That way I can have easy access to my coupons and use my list. While in the store, pay special attention to clearance areas. More often than not you can get great bargains that you have coupons for. For example, the other day I found a Schick men's razor, normally $10. It was marked down to $5 and I had a $4 coupon, so I paid $1 for a $10 razor. You never know what you might come across!
At checkout, watch your cashier and the register very carefully. Some stores registers may have problems and do not scan correctly. At my local store, if a product scans at the wrong price, the item is free. This is where the rule "know your stores coupon policy" comes into play. Also, make sure your cashier scans *all* of your coupons. There have been many times where the cashier misses a coupon. You never know, we are all human and prone to make mistakes, but a cashiers mistake is less money in your wallet.
I love to look at my register receipt and see how much money I have saved. In the end, it makes all your effort worth it!