I recommend reading The Lean Startup. I found it full of good ideas. One example: cohort analysis. You might already be familiar with all the concepts and ideas in the book, but even then I think the various examples of real companies doing some of these things will be inspiring.
The Lean Startup is good but I found Running Lean to be much more tactical. Plus the guy who wrote it, Ash seems to be very active in providing content beyond the book in his newsletters, blog posts, and his Lean Canvas.
The top rated review of The Lean Startup basically trashes it, saying it never gets very specific, and is sort of a vehicle for Eric Ries to sell himself.
There's definitely some self promotion in the book, and at times it can be a little repetitive. It's also fairly introductory and the information in it can perhaps be found on various blogs, etc.
It's a good introduction however for anyone looking to move beyond a trial and error approach to startups.
