When writing a thesis you have two problems: writing and the ideas you are trying to convey. When you need to write a thesis, start by writing something, anything, every single day. Non-trivial amounts, and expect to throw it away. by the time you have to write the important stuff for real, the writing is second nature and you can concentrate on the bits that really matter.
So it is with implementation of startups. Do it several times over. Pick something and see it through to launch. Don't expect to make money from it, but get a minimally working, not too shabby version actually working with other people using it for real. Until you have that experience, making a product to make money requires that you solve more problems at once than you have time for.
Experience failure to learn about success.