I've personally read these ones but I still have like 500 on my to read list:
-None of Your Business: A Winning Approach to Turn Service Providers into Entrepreneurs (short read, good introduction to the mentality of this)
-Book Yourself Solid by Michael Port (long but great!)
-Time Management Magic (for figuring out what's important)
-Happy Money (So good, just felt I should include it, of course about relationship to money which is a huge element here)
There are so many more of course but these kind of get you going in the right direction. Youtube and blog articles also have great content!