I had this at uni. It was a long time ago, so I can't really provide references.
If you want to learn something new, you need to reinforce each time
When you already know you can do the whole thing, then it's a good idea to start intermittent reinforcement. It should gradually go from 100% to 0% rewards, so you could e.g. take a d10 and roll it; first week anything over 1 gives you the reward, second week - anything over 2 etc. The die is essential, you need to randomize the reward, not just say "every 1 out of 4 gets a reward" - that in fact works worse than 100% rewards.
I used it to potty train my kids, worked like a charm.
http://measureofdoubt.com/2011/04/12/pulling-levers-killing-monsters-the-lure-of-unpredictable-rewards/ (how do I put a link like this in a word with blue letters?)
I've read that unpredictable rewards associated with a behavior actually encourage that behavior more effectively than consistent rewards.
The optimal habit-forming figure given in the link above is a 25% chance of reward for each instance of performing the behavior.
My hypothesis then, is that if I want to establish a habit by rewarding myself upon successfully performing a certain task, I should reward myself only 25% of the time if I want to ingrain the habit as forcefully as possible into my unconscious.
Anyone else think so, or have any other research to add?