Everyone has their own way, but here is my best tip: START SMALL. You'll want to get a hang of things and comfortable with couponing before you start making bigger transactions.
Be prepared! You want to know about the sales before they happen and you want to have the coupons ready. Just do your research on couponing websites that will let you know in advance what coupons will be in the newspaper for the week or when they become online.
Be organized! Use whatever method works best for you. Leave you coupons unclipped and sorted by date until you need them, or just clip them ahead of time and put it in binders or envelopes.
Know the coupon policy of the store you're going to shop at! If you know that you're going to shop at a particular store, such as Harris Teeter, know ahead of time what you can and can't do to avoid any problems, delays and embarrassment. Some stores, such as Wal-Mart, allow coupon overage (e.g. buying a $1 item with a $2 coupon) to be applied to other things you don't typically have coupon for, such as meat or fruits.
Stock up! Every extreme couponer has a stock pile. It doesn't have to be huge, but buy enough to last you until the next big sale. Many things will go on a huge sale every 2-3 months.