Just to add in to what others have already said....
The set time, journal keeping, and all that are excellent. I would recommend them as well. I stick to routines better than I stick to "yeah, I'll do it when I find the time". No. *Make* the time...
When I do personal training out of the school (and sometimes even when I am there), I will pick particular strikes or kicks to work with. For example, I might work on my uppercuts and roundhouse kicks one night. I try throwing them from different angles, try to see if I can reduce my movement but increase power, experiment with them in general. After working with these for a while, I will work with techniques that include those strikes, again playing with variations. After doing this for a while, the strikes/kicks become much more of a familiar tool, and it gets to be quite fun if you imagine different scenarios to test out your variations.
I would also recommend music to go with your routine. Depending on your mood and personal tastes, of course, but pick something that will get you moving. It's often harder to quit when you have a driving beat going. Maybe try to work a heavy bag to the rhythm of the music?
Anyway, just a couple of thoughts.
Peace--