One way to make the basic piano blues sound more interesting and musical, is to start with a beginning before you play your repeated 12 bar blues scheme. Below are two blues beginning examples in the key of F which you can try and practice.
Both examples are using notes of the F blues scale.
The F Blues Scale
The first beginning starts with a repetitive theme of triplets moving down from the blue note or sharp fourth (B). Then the blues is introduced by one bar played with the left and right hands in sync. Note that the eighth notes are not played evenly, but in a shuffle rhythm where the first note is longer than the second one (long-short, long-short).
The second beginning starts off with a small run down the blues scale with some double stops. In the second bar the fifth (C ) is emphasized, creating a tension that wants to resolve to the one chord of the blues (F). The small notes (A♭) next to the A notes are grace notes, which are played by sliding off the black key (A♭) into the white key (A).
You can find or create more blues piano beginnings by listening to blues records and trying to play or transcribe some beginnings that you like. Your blues will definitely sound more interesting!