The trick here is, give yourself and no one else the url for your form. Bookmark it on your smartphone. Fill it out all day long, whenever appropriate. I've been tracking all my bodily inputs and outputs, as well as mood, sleep habits, and a couple other things. I generate about 10 or 15 lines on the spreadsheet a day. The form takes about 15 seconds to fill out, which I do during downtime (like while I'm peeing...).
At the end of the month, I'll have more than 400 datapoints. Since it's in a spreadsheet already, no extra tabulation is necessary. As long as you design your form/spreadsheet combo with some insight, you'll be able to learn things about yourself that you never knew before.