We humans are a funny lot. We are so diverse that any generalization usually has more exceptions than you can count. And that generalization is no different!
Having said that, let's look at some of underlying reasons why we procrastinate and prevaricate.
1. I'm bored.
2. That looks more interesting.
3. It is too hard.
4. I'm afraid of failure.
5. I'm afraid of success.
6. I'm not worthy.
Not an exhaustive list, perhaps, but probably six of most common reasons for not getting things done.
In order to really start achieving your potential, you must first analyze yourself to determine which of factors (or which combination) apply to you.
Only then can you start to construct strategies to combat them.
In general, though, solutions are either internal or external. If you find that you are a person who needs help in finishing a task, that help must either come from yourself or from others.
Internal spurs are such things as promise of a reward when job is done - a candy bar or a new outfit, you have to decide what is a fitting reward for yourself.
External spurs tend to be of 'keep me honest' kind. Appoint a close friend with whom you can share your plans. This person becomes guardian of your honesty and will call you regularly while your project is in hand, to check on progress and to keep you on track. It may sound very simple, but it works.
The secret to either internal or external motivation is in setting realistic goals.
"How do you eat an elephant? - One bite at a time."
A friend's son was panicking recently because he had been set a project at college which had thrown his mind into turmoil.
"I've got to write a 100 page project on history of automotive design," he told me despondently, "and I've only got 4 weeks to complete it!"