How do I fill a gap between wall tile and acrylic shower base
If you have access to the same tiles that you used, you could cut them to size (you may want to consider using a good cutter or wet saw). That way you can caulk the space in between the tile and the acrylic shower base. If you don't have any extra tiles or can't find any more of the same type, you could find a nice complementary looking small tile and install that instead.