You can spend your whole day worrying about something but it won't resolve until you work on it so it's no use worrying about about a problem when you're working.Either you immediately resolve the concern in your head or go for a walk and rest for a bit to free your mind.

2. Do Not Worry So Much 

Focusing is about saying no

To exercise your focus promise yourself that for next 15 minutes you'll not get up or touch phone or walk around. Do the task with utmost will

10-15 Minutes 

For each day determine 3 tasks that you must complete by the end of the day. Keep reminding yourself of your goals can help you complete it.This relieves pressure and satisfaction from completing tasks makes you confident.

5. The Rule Of Three Tasks

No matter what the task is you can't complete it if you have your phone lying around you.Make it a habit to stay away from your phone when working. Notifications can wait.

1. Stay Offline

Since you are already reading this you're on right way. Just read whatever you find interesting it doesn't have to be related to your work or academics.Reading makes our brain sharp and makes it think better.

3. Read More

Worst enemy of your focus is other people pestering you for things. Learning to say no is a skill not everyone has but anyone can learn it by just politely denying the favor/request.

6. Learn To Say "I'm Busy"

Confidence!Trusting yourself will help you stay focused, work harder and do your job better.Say to yourself, "I can complete this task efficiently"

4. Think Positive 

Whether you think you can, or you think you can't - you're right.

You won't be able to focus if you're body isn't strong and your mind isn't focus and you get tired by climbing up a fleet of stairs . Do these 3 things:<ol><li>Eat healthy food</li><li>Sleep well</li><li>Do exercise</li></ol>

9. Healthy Body, Healthy Mind

Do the boring tasks first when you get up in the morning not only this will free your mind from thinking about it rest of the day since we are most energetic after waking up we can do even the things that we don't enjoy doing or just simply don't like it.

8. Start With The Hardest

Calm down you don't have to buy a shed. This warehouse costs nothing. Whenever a thought comes in your head while you're focusing on stone other task just simply write down that thought in a paper or in your phone by doing this not only you will free your mind from clutter but also have a nice toh do list so you don't forget things

7.  Have A Warehouse 

Do you want to achieve your goals and succeed at work and in life?So stay focused. Focus on what you do. Do one thing at a time!Learn 10 ways to stay focused and increase your productivity.

3. Read More

Similar ideas to 3. Read More

1. Do not finish it.

Read the text more than once

Read With Context