Shopping lists are so easy to write. Sticking to them? Not so much.

Mind Over Money author Eric Tyson has formally researched this truism, and even explains how to overcome our faulty psychological wiring so we can do things like, well, stick to our shopping lists. At least I think he does.

When I went to the bookstore to pick up a copy of his book, I got distracted by the latest issue of Elle Decor, a new day planner, three birthday cards, and a friend of mine in line at the checkout counter. (Remind me to jot down the title in the "To Do" section of my cute new pocket calendar.)

How to keep yourself honest at the checkout counter
Here's your first tip to trimming your overall spending tab -- a shortcut, even: Stop reading right now and print this page. Now put it in your wallet, purse, pocket, shoe, or wherever you're most likely to notice it before you reach the cash register. Vow to try to follow at least one of these rules (or even three, if you're in the mood for extra credit) the next time you're in a particularly acquisitive mood.  

Ditch the plastic and pay with paper money. The advice may be obvious, but curbing credit card use is one of the best ways to squelch a spending problem. Keep the cards at home and carry cash, checks, or a debit card. An obstacle? Yes. But so is a mountain of credit card debt.

Record every retail atrocity. In that cute little day planner, write down everything you purchase over the course of a week (or two days or however long you can stand it before you gag). Just the act of noting the "non-essential purchases" will likely curb your enthusiasm at the checkout counter. If after a week you find yourself going back to old habits, reinstate the exercise. (Your shortcut here is to use free -- and scarily simply -- financial tracking software, like See "Stop Mistreating Your Money" for more.)

Drag your best "frenemy" to the mall. The best spending deterrent in the world is a frugal friend who isn't afraid to nag (good friend, shopping enemy). Or roll his or her eyes. Or hold onto your wallet. When they're not available to play bad cop, see your inner money shrink. In other words ...

Do some shopping self-help exercises. When you grab that [insert your last impulse purchase here], even if it looks fabulous when you try it on, don't put it in your cart until you ask yourself this one important question: Do I need it? C'mon. Do you really? That's what I thought. Author Pamela Danziger (who wrote Why People Buy Things They Don't Need) says that we shop to gratify a desire, and the actual act of consuming (strolling the aisles, trying things on), rather than the item consumed (actually buying the aforementioned impulse item), satisfies our emotional needs. She's right. Often when I walk out of the store empty-handed, I feel perfectly sated and proud about the money I "saved" by not spending it. Which leads us to ...

No fuzzy math. There are lots of ways we convince ourselves that buying is better than putting back on the shelf. "I get miles or cash back for this when I put it on my credit card!" "If I amortize the price of these shoes over the number of times I know I'm going to wear them, they're practically free!" "I just returned three rolls of shelf liner, 'freeing up' $22.02 to spend on candles!" Yes, I'm quoting my own favorite excuses. (For more advanced -- and accurate -- math, see "Budgeting for Lazy People.")

Unsubscribe. Stay out of the hot spots. Don't go to the mall just because you're bored. When you do run out of detergent and light bulbs, steer your cart clear of the clothing department (or whichever "zone" triggers the "I wants") and go straight to household goods. Online shoppers can find themselves deluged with "Special Online-Only Sale Now, Yes We're Talking To YOU" emails. Take your name off the mailing lists. Trust me. (See also: "Retail Tricks That Make You Overspend.")

Institute a waiting period. Online shopping is sure convenient. Too convenient if you have no impulse shopping control. Instead of clicking "Buy," bookmark the page or use the email-a-friend (meaning yourself) feature. Let it simmer for a while. You'd be surprised how after a few days, the urgency of that "must-have-it-now" item fades, if you even remember that you wanted it in the first place at all. If you're in a bricks-and-mortar shop, don't put it in your cart the first time through. In fact, don't even grab a cart or ask a salesperson to hold something.

If you really, really, absolutely need whatever it was you saw (and your shopping frenemy agrees), go back and buy it the next day. But pay cash. And stick to that list. You know ... if you can.

For more Foolishness:

Consumer finance Fool and shortcut fan Dayana Yochim no longer mistreats her money. She will be tracking her spending for at least an entire week. Starting tomorrow. Promise. The Fool has a disclosure policy.