The urge to complete things is strong in people. Incomplete things feel messy, uncomfortable, and play on the mind. This can be used a simple and powerful tool to achieve things, or learn anything.
The method is simple. If you want to achieve something, imagine the achievement as a completed thing, then see and feel what parts of it you have achieved so far and which parts are incomplete. By this visualisation, and by monitoring and repeating it, you will gain the motivation and clarity of purpose to achieve your goal with almost no other effort. You unconscious drives will tell you what to do to complete everything nicely, neatly, totally.