What projects should I work on to keep my skills sharp?
For some project ideas, you may want to Google/search the internet for some inspiration. We personally love the website from Jen Dewalt. Some of her experiments may provide you with inspiration.
Perhaps you would also like to look at Free Code Camp, where you can get better at JavaScript while you use your skills to help non-profits!
Reddit threads and Stack Overflow are full of ideas as well.
JavaScript30 provides a month of small daily JavaScript Exercises.
This large list of JavaScript projects is bound to have something interesting to work on!