People try all different ways to do the warm ups, like 1 letter a week, 1 letter for 2 weeks etc. The best way is to do the official letter of the day, no matter how well you know it. Just synch up immediately and try to keep up. One day you'll have them so down you'll be able to do them on a timer in the advanced classes, each flow is 3 minutes with a 1 minute review in between.