I'd take a piano sound that goes a bit deeper than the one you use. Also the happy sounding sounds at the end I'd try to give somewhat a less surficial sound. Tip: I hear a bit of distortion on some of the sounds. What this track needs, is a bit of volume balancing and a bit of mixing and mastering...
Newbie here. I just started learning LMMS and I was able to create a short simple track. Appreciate any feedback, especially on how I can make my music better using the application. :)

https://soundcloud.com/introversed/intro