Pay Attention To Your Thoughts
The first thing you need to master is your attention span. Anything is going to be difficult to commit to memory if your thoughts are scattered and you are not truly concentrating on the topic at hand. In the same way someone can will themselves to memorize up to 10,000 digits of the unending 3.14159, you can will yourself to remember things if you tell yourself “This is important. I need to know this” over and over. Doing so will help you align your focus.
If you are struggling with paying attention to whatever it is you are trying to memorize, then you should eliminate distractions. Try blocking out noise or relocating to some place where you can relax. You can do other things to help focus, too. Incorporate note-taking or visualization or even discussing the topic with other people.