I can not speak for cameroncowan, but I was tempted to ask the same question. For which reasons are you interested in forming the habit of experimentation? For example, is your main motivation to pick up low-hanging fruit, do you have some particular question concerning yourself (such as diet, medication, habits, etc.) that you wish to test, or do you perhaps wish to become more adept at spotting moments ripe for experimentation in the long run?

The examples in this thread are of different sort, and require different approach. The links posted by coyotespike show examples of long experiments on yourself, where you sit down once a day for a long period of time (weeks/months) to draw a conclusion. The (fictional!) HPMOR example is a clear case of low-hanging fruit: taking a couple of hours to find a better battle strategy is a good investment of time. I'm not sure about the Feynman example, but this also seems to be a low-hanging fruit example (if the experiment would have taking him a month I'm not sure he would have done it). So, what sort of experimentation skills are you looking for?