Focus means to keep your attention on a certain aspect, to concentrate. This increases your ability to realize your goal or dream.
How do you obtain focus? Work with a daily and weekly schedule. Enjoy regular stimulus-free breaks. Get used to ending your day consciously, so you can let go of your emotions and clear your head. In this way you discharge so to speak and your focus is turned off to recharge your battery. But focus has more to it, also keep in mind of nutrition, sleep, exercise and stress reduction.