By nature I am a list-maker. I almost always have a notebook with me that I constantly jot things down in, primarily in the form of lists. I write errand lists, grocery lists, shopping lists, cleaning lists, lists of things to pack if I go somewhere, to-do lists, and well, to exhaust the phrase, the list goes on and on. Lists are a frugal person's greatest ally because they are a great tool for saving money.
Many times people only use a list when they shop for groceries-however, I think that lists are beneficial in ALL shopping situations. For instance, at Christmas time I make lists of exactly what I plan to buy for others and how much I intend to spend. I compare the list to sales ads that come out and see where I can get a good deal on my intended purchase. Even when I need new clothes, I prepare a list of what I need, which limits my spending and my overall consumer-drive. If you're like me you want to shop sales to get great deals. If you're not shopping with a list, often all you end up with is a "great deal"-not something that you need. Skirts being on sale for $8 does not justify the purchase of several skirts. The need for skirts justifies buying more skirts; not the price. This is a lesson I have taken a long time to learn. I have often bought things when they were "dirt-cheap" and then never used them! It's wasted money even though at the time I thought it was a "steal".
In summation, make a list before any shopping trip and prioritize what you actually need versus things you don't need. Remember also that shopping is never meant to be a hobby!