Well try the mantra before bed, tell yourself that you will "realize when you wake up and not go back to bed" like yesac suggested. You could also try to make it a point not to turn off your alarm right away and let it wake you up a bit. I realize it will be difficult considering most of the time you dont even remember turning it off in the morning, but by setting your intention on waking up fully during each WBTB you will start to get better and better.

Perhaps you could try placing your alarm just out of arms reach so you are forced to physically get up. This isnt ideal because in the end you will want to lie completely still, but it may help to get you into the habit of fully waking throughout the night. Ultimately you just want to make a conscious effort to be more aware of waking up. This alone will help tremendously. It will just take some practice and some time for you to observe your waking process and be able to recognize it more easily.