Set Deadlines
To manage your tasks, set deadlines.
Having a deadline helps you focus on the task at hand and how you are going to do it.
Having a deadline ensures that you can divide up your work, so it fits within the time frame required.
Without a deadline, work seems to expand to fill up every available space. With a deadline, you are forced to contract it into a space that you require.
It is a test of skill and determination.
So, set yourself a deadline for the tasks you need to achieve.