As said before, breaking up things to do is a fine art. If you know and adopt some Agile Movement techniques, you have probably faced these problems already, so you have an advantage; otherwise you will need to make a little more effort, but it isn't anything you can't achieve.

Consider you have been assigned to add the Remember Me check in the login page of a web application, like the following one:

This feature is quite small, but implies changes at different levels. To accomplish this, you'll have to:

1. Modify the UI to add the check control.
2. Pass the is checked information through different layers.
3. Store this information somewhere.
4. Retrieve this information when needed.
5. Invalidate (set it to false) following some kind of policy (after 15 days, after 10 logins, and so on).

Do you think you can do all these things in a shot? Yes? You are wrong! Even if you estimate a couple of hours for an ordinary task, remember that Murphy's Law applies: you will receive four calls, your boss will look for you for three different meetings and your computer will go up in flames.

This is one of the first things to learn: break up every piece of work into small tasks. No matter if you use time-boxing techniques like the Pomodoro Technique or not, small things are easier to handle. I'm not talking about splitting hairs, but try to organize your tasks into things you can do in a defined amount of time, hopefully a bunch of half-hours, not days.

So, take paper and a pen and write down all the tasks, as we did before with the login page example. Do you think now you can do all those things in a small amount of time? Maybe yes, maybe not: some tasks are bigger than others. That's okay, this is not a scientific method, it's a matter of experience; can you split a task, creating two other meaningful tasks? Do it.

Can you? No problem, don't try to split tasks if they lose meaning.

Make a little notebook, like the one in the following picture - it will become one of your most precious tools: