When I was a kid, one of my favorite annual events was the arrival of the Sears Holiday Catalog. This was a giant book, multiple inches thick (at least in my childhood memory) filled with all sorts of wonderful gifts that could be purchased. Of course, I ignored all the boring household and clothing sections and immediately turned to the toys. Oh, the glorious toy section. So many awesome things to look at and bookmark and wish and hope for Santa to bring.
I still sort of do that, though not with the Sears catalog. I don't even know if it still exists, and if it does, it doesn't get delivered to my house.
These days, much of my shopping is done online and let's be honest, it's all too easy to just press a few keys and boom! The item is on its way to you. But that's not really the most frugal way to shop, nor is it great for anyone trying to stick to a budget.
So what I do is a lot like what I do when I was a kid. I make a wishlist.
I do this in a couple of ways. In my paper planner (yes, I still keep a paper planner), I have a running list of things I want to buy. Not specific brands or styles, just things I want. A deep freeze for my basement. A power meter for my bike. Et cetera. The list is there for me to refer to and save for.
But then there are the things that I know that I want, I'm just not ready to buy them. They might be big things or they might be small inexpensive things, like a new book. In that case, I keep an online wishlist. Mine happens to be on Amazon.com. They have a great widget that you can install on your browser so you can just click and add an item to your list, regardless of whether it's sold at Amazon or elsewhere. I'm not shilling for Amazon in this post, it's just what I use. I know other people use Pinterest in a similar manner.
It's a great way to keep track of items I would like to buy, and then, when I'm looking to purchase a book for a trip, I know where to go to figure out what I want to buy. It also keeps me from the small impulse purchases. I don't need it now, I'll just write it down and wait. Many people use this to determine whether or not to make larger purchases as well. Write it down and wait. If you still want it in a few days, then consider it.
Try the wishlist plan for yourself. It's amazing how such a simple plan can save you money.