music composition help!Watch
To make it sound mysterious, you could start with a simple melodic idea, which you could contiune to develop (maybe have some light use of ornamentation, like mordents) in the first part (don't know how many instruments you're writing for or if it's just the piano?), then introduce the first melodic idea in the second part (e,g in the LH piano) and develop it, but take the melody somewhere else to end up with a kind of conrtapuntal texture . Or you could just play with building up the texture slowly.
Alternatively, you could do a groundbass composition as having a strong bassline to build on and tie the music together is a really good way to get started if you're stuck.
Just some idea, hope it helps.