Where do you focus your attention? Do you focus on one thing or does your focus jump from one thing to another, never staying in one place long enough to really accomplish anything? Focus does not mean the same thing as concentration. Concentration means sustained focus combined with intense mental effort. Concentration involves time, focus does not. Think of a pair of binoculars. You look through them and adjust the focus to your eyes and the distance of the thing of interest. Focus involves pointing the binoculars and sharpening the image. It does not require sustained looks in the same direction. You can change your focus quickly or slowly. Concentration, on the other hand, involves sustained looks in the same direction while examining and trying to understand what you see.
You should include both operations when you work to solve problems. Concentrate on the problem to understand what you know and do not know about the problem. Then draw on your instincts and let inspiration give you an idea of where to start. Scan the environment for hints about how other people have solved the problem, focusing on everything you can find. Concentrate on synthesizing a potential solution. Then concentrate on your work and solve the problem.