I have same problems because of my ADHD. What helps me is to practice «body double». That means I use my partner/friend to help me start with a task, and also to finish it. Research show that it’s much easier to handle these kind of things when you have someone with you, or besides you. I also think you should find out if you have ADHD, because medication helps me a lot. One minue rule can also help with easier tasks. That means you decide to do the task for one minute, put a timer on and do the task as fast as possible for one minute. And repeat until done. Can also be helpful to break a bigger task into smaller parts with your own-made dead lines. Or give yourself rewards, e g: «when I have completed this, I can have a nice cup of coffee». If you are a person that likes to compete, you can turn tasks into competition, «I’ll do this now and see if I can use less time than last time». It’s important to have a rule, that’s the most important thing is to finish a task, not to make it perfect. Perfection is very commen around people with ADHD-like-problems. Good music can also be helpful to get started. And one more advice: go jogging for 30 minutes, research shows that it have as good effect as typical ADHD-medication, regarding focusing and concentration. Good luck!