ulepšavati

1. to beautify; to brighten up
   Cveće na terasi ulepšava ceo stan. — The flowers on the terrace brighten up the whole flat.
   Tvoje poruke mi uvek ulepšavaju dan. — Your messages always make my day.
2. (of a story, the truth) to embellish; to sugarcoat
   Ne ulepšavaj priču, reci tačno kako je bilo. — Don't embellish the story, tell me exactly what happened.

The perfective is ulepšati; ulepšavati se means to make oneself pretty.