If you need to use these sites to make enough money to make ends meet
, as opposed to, say, just a few bucks to help out with groceries, then you'll want to make sure that you're working at around the same time every day, for around the same amount of time. Of course, the freedom of working on the web means that you can take days off whenever you like and so on, but if you at least try to work around the same hours, more or less, then you'll find it much easier to make more money with your survey sites.