I have too many projects. How do I pick one and focus on it until it’s done?

If you have many projects pick the most important one and block between 2 to 4 hours in the morning to work in it.
The thing is to not allow you to be distracted during those hours and do not engage into other activities. One thing that might help is having a " distraction notebook" where you note everything that popup in your mind during this focus time.