The best way in my opinion is not to overwhelm yourself.

Go one ability at a time (I started with Serpent Sting way back in the day) and bind a new ability every couple of days. eventually once you get used to it you can add more at once. You'll be shocked by the results. Keybinding is so much better than clicking it's unreal and you'll quickly see the benefits.

Eventually you'll get to the point where you literally won't use abilities that haven't been keybound because it's such a hassle clicking on them, that's when you know you're doing it right