This isn't really about promotion, but remember to add explicit license terms, so that people know what to expect.

Have you shared it on any game dev subreddits?

tileset looks nice, cant quite put my finger on what it reminds me of. Game Boy Advance perhaps..

anyways,, have the occasional sale and keep on making assets so you can form bundles too sell. thats a couple of ideas that will help you get exposure on here.

Good Luck