Procrastination has nothing to do with disciplining yourself or 'just doing it' This is the most common misconception about procrastination and will instead achieve exactly the opposite of what you want. Let me explain:
The reason why human-beings procrastinate is to feel in control of their life. The act of rebelling against an oppressor, an authorative figure telling you what to do, is your way of regaining mastery over your own fate. Very much the same way kids throw a tantrum when their parents order them to do something, the procrastinator puts off tasks because he has come to harbor resentment against the thing to be done. Why, you ask? Because in your admirable will and ambition to achieve your goals, rather ironically, you have created the only thing that can stop you from reaching your goals: a separate mental authority figure causing unneccessary internal strife. You have created a bully out of yourself.
Start listening to the way you talk to yourself; Instead of punishing yourself for not following up on things, you need to learn to let loose. Adopt the belief that you have the natural tendency to work productively and act creatively. Nobody needs to man up, shape up, or be disciplined. Stop framing the world as if it is a constant struggle to get things done, instead start viewing life as a sequence of awesomely fun and exciting things to work on.
Good luck, Edo van Royen
edit: Humbled by your comments, thank you all. I write pretty regularly, just never on a public forum like this.
note: I notice my writing could use some nuance. Painting an extreme is just a style of writing which helps bring across a point. Obviously there are things that are objectively less fun to do.