One things that I found really helpful in establishing a regular meditation practice is to make a meditation a part of your daily routines. For me, I shower and brush my teeth together everyday, and have no place to rush off to after doing those things. So adding medititation to the end of that chain of routines fit naturally, and made it so I really couldn't forget (or "forget") to meditate.
If I couldn't do it at the time, at a minimum I was forced to engage with myself about why I wasn't doing it, and make an agreement with myself about when I would be doing it.