Some great suggestions here, 'specially Charlee's.
I worked in the book trade for many years...selling books is a thing many would like to do but is very hard graft and the margins tight. I note you self-publish...this is not a negative, but have you thought of submitting your manuscript/s to a publishing house?
If you prefer to not go through a publisher, perhaps approach a book marketing agency, they will show your books when doing sell ins to booksellers and library suppliers. This is an excellent way to sell multiple copies and to get repeat business and possibly public lending rights (not sure how that works in the USA). An agent will of course expect a commission, but if the sales volume is there it could work to your advantage.
Anyway...looks like you now have plenty of food for thought. All the best with your endeavour.