Choosing the Items
9. Don't avoid popular games just because they're popular. Frankly, popular games are popular for a reason: they probably do fit a lot of list topics, since most lists talk about things games have done particularly well. It might seem predictable to put Ocarina of Time or Final Fantasy VII in certain lists, but that doesn't automatically make it a bad thing. If a popular game really works with your list's topic, then don't be afraid to use it. Sure, Chrono Trigger makes an appearance on nearly every list of Top RPGs ever, but that doesn't mean you shouldn't use it if you're writing something similar. (Now, if you really don't think a popular game fits, then don't include it -- all I mean is that if popularity and predictability is your only reason not to include a game, you should probably include it anyway.)
10. Don't default to popular games if you run out of ideas. At the same time, however, don't resort to popular games just because you can't think of anything better. If you've brainstormed a list of seven games, don't start thinking about Ocarina of Time or Final Fantasy VII and try to talk yourself into thinking they fit. Sure, those games have great music, but if you really don't believe they have among the best music ever, don't include them in a music list just because they're popular and easy to write about. If you run out of ideas, do some research. Check Google for similar topics. Ask around on some social boards or on the Top 10 list board. But don't fill up your list with a popular game and then try to sell us that Super Mario Bros. 3 had some epic plot twist or something.
11. Be prepared to do some research. No one has a sufficiently comprehensive knowledge of gaming, or likely even any corner of gaming, to write the perfect list all their own. For example, if I asked you to name the Top 10 Plot Twists in gaming, you could probably think of ten: but that doesn't mean you should automatically make a list of those ten. There are a lot of games you've never played, and it'd be a shame to leave them out of your list just because they never fell on your radar.
The key is that a Top 10 list doesn't necessarily have to be all games you've played. In my Literature-Based Games list, I've played a grand total of one of those games, and it took the 10th spot. If you have a good idea, though, you can do your research and find out what else would fit into your topic. You can find games that you've never played, and research enough about them to include them. There's nothing at all wrong with that; it'd be more wrong to assume you know everything about your topic off the top of your head.
12. Take your time. Don't sit down one day and decide you're going to ram out your ten choices right then. I've got a document on my computer of list ideas, each with four or five games listed below them. If need be, I can go do some hardcore research and fill out my selections, but it's more effective to just let the idea simmer for a while. As I go about my normal day, reading sites and posting on GameFAQs, oftentimes an idea will come up for a game that fits into a list I'm already working on. That's a very organic way for a list to form: the less forced and the more natural, the better.