You should look at his op. 2 set, the first is a rather famous slow etude, the other two are pretty much unheard works, there are some beautiful preludes in his op. 11 set and Op. 3 consists of not very difficult mazurkas, op. 9 has a great nocturne for the left hand, but all these works are rather Chopinesque, his later works are insanely difficult, and apart from the sonatas I'm not very familiar with these works, so maybe someone else could give some advice here? His earlier works are a great start though!