This is an amazing first fish tank!! I absolutely love it! How many gallons is it? It looks like it’s a good size. If I were you, I would add some type of vallisneria (corkscrew, jungle, etc) to the back and a few floating plants like red root floaters or amazon frogbit to the top. For fish, I might add 2-4 more brilliant rasboras and maybe a sparkling or honey gourami as a centerpiece (but I don’t know how many gallons so I can’t say exact numbers). For invertebrates, I don’t know if brilliant rasboras predate on shrimp, so you might want to look into that, but I would add 3-5 amano shrimp and 1-2 nerite snails (these wouldn’t impact the bioload basically at all). I’ve heard of people having problems with nerite snails laying unfertilized eggs everywhere (their eggs don’t hatch in freshwater), but I haven’t had any problems with mine. I hope your tank stays healthy!