If you want to use coupons, but don't think you're organized enough, here's an easy way to start.
All you need is a envelope, and the weekly coupons. When you see a coupon for the item that you normally buy, simply tear it out. If you want to be neat, then sure, grab some scissors. But, you can just as quickly tear around the edges--it doesn't have to be perfect.
Place the coupons in the envelope.
The next time you're in the carpool line, in a waiting room, etc., think about your grocery list. Pull out the coupons, and if there are any items that you are in need of, simply place that coupon in your wallet next to your cash or credit card.
It's easy to remember the coupons when the are right next to to your payment method.
There are hundreds of coupon organizing systems, books, and websites. You can certainly compare them and find one that fits your needs.
In the meantime, however, this is a basic "envelope to wallet" system that doesn't take long at all--especially if you're simply waiting in line at car pool.