Every time you do something that you do frequently during the day -- for example, pick up your phone to use it -- stop for a few seconds and mentally ask yourse

Every time you do something that you do frequently during the day -- for example, pick up your phone to use it -- stop for a few seconds and mentally ask yourself, "Is this real?" Once you're in the habit of doing that, you'll start doing it in dreams, too. And in dreams, you're very likely to realize things aren't real, and that you are, indeed, dreaming. That's the technique that works best for me.