A lot of time I will see a movie or TV show and not like the ending so I start messing around with my own version. Many times I will have a dream and it will stick with me all day and I will play around with it until I like the story then jot it down for later use.
I find when I think I have 'writer's block' it's because I am stuck with where my story should go. So I first try outlining a bit more to see if that fixes things. Then I skip ahead and write some scenes I'm excited about and if all else fails I will go write a completely different book that is 100% for me and then come back to the one I've been stuck on with a fresh look on it.
I read them the first few days after launch to make sure everything is ok. Like when I launched The Cowboy and His Runaway I found out by day 2 the editor I used was horrible. So I had to quickly get the book re-edited. After that, I don't read them really except maybe every few months to see if there is any place I can improve my writing or the series.
Publish sooner! The books I am publishing now are ideas I've had for years! The Rock Springs series started with Sage and Colt's story in book #2 and it came to me over 10 years ago. It's been sitting there on my ideas sheet for 10 years before I finally said I'm going to publish this series no matter what.
Write what you love. If you try to force your self to write what you think will sell then it's not fun anymore. Also don't be afraid to take a break and read books from your favorite authors or binge watch that new TV show. The inspiration nd idea you will gain are much more valuable than any time you think you lost not writing.