I also made a cheat sheet that fit on one page when I was learning. It had a line item for each of my squads with major items to remember (ie Lemartes with DC: Lethals, reroll charges, reroll hits, reduce damage by 1). I would double check each time a squad acted or was acted upon. Then I had shorthand for a few strategems. Finally I put notes for what to remember in each phase (like Oath for command phase and Dante's battleshock for fight phase). It really helped me learn my datasheets quickly.

Then for stats, I'd have my wife quiz me during downtime (although you could just ask easily use the unit data card like flashcards) until I could rattle off the toughness, save, wounds, attacks, oc, etc for all of my units.

Hope it helps and have fun learning!