There are several exercises to increase focus. First of all, try to write down your goals. By doing this and keeping the list within sight, you constantly remind yourself of your goals. Did you set a goal that might be too big for you to reach within a reasonable amount of time? Break it down by creating smaller milestones.
It is also advisable to do visualization exercises. During this process, neural pathways are created that make your brain think you actually are performing that action. When you want to do visualization exercises, find a quiet place and relax. Close your eyes and begin to breathe in and out slowly and deeply. Now think of a situation in the future that you would like to achieve. For example, successfully participating in an important sports event. Observe how this feels. Use all your senses and take in all the details. Not only does this make you feel better prepared for the actual event, but it also helps against nerves and reduces anxiety.
Lastly, practice concentration exercises as often as you can. Without a fair amount of concentration, you are not able to complete the tasks you need to do to achieve the goal you have set for yourself. Examples of concentration exercises are working out and meditation.