To be honest, I found that the only way to remember the commands is to commit them to muscle memory. However, this means coding enough in vim that you look things up enough for them to just stick.
Once you know how to switch between modes, it's easy to use vim as a basic text editor using the cursor keys.
At that point I wouldn't start looking things up all the time. Just set out to learn one new command or shortcut every two days, applying it in your daily use. Usually that's enough to get them in your mid-term muscle memory, so that you continue to use when you move on to the next command. The Vim pocket guide is great to choose what's up next.
I was already fairly adept at Vim when I applied this method to teach myself less frequently used Vim commands.
