Any and all of the Chopin mazurkas. They're all lovely miniatures, usually 2-4 minutes long. Brilliant works, and some of the most authentic Chopin pieces.
Alongside that, the rest of the Bach 2 part inventions, maybe some of the 3 part before you move along to the WTC.
Mozart sonatas do wonders, as well. K545 is a good one to start with.
Check out the Scarlatti sonatas as well.
Also listen to some of the Schubert waltzes. One of our members here, I think his name is josh32948 or some combination of the numbers "32"(32 Beeth. Sonatas), "9" (9 Beeth. Symphonies), and "48" (the number of Bach preludes and fugues in both volumes of the WTC) has posted several of them, his playing is very good. You should definitely check it out.
Then, you can tackle some of the Schubert impromptus, perhaps.. But those are far ahead in the road, they're little gems of music.
If you want some impressionistic music, check out Ravel's prelude in a minor, one of his miscellaneous standalone works (I'm studying it right now for the musical value), it's quite easy technically speaking, though the middle section can get your hands in a twist.
Feel free to PM me with any questions.