You’ll want to pick up Hustle Dance ASAP, because it’s the best healing skill from the moment you get it until around the beginning of Act 3. Sylvando’s Showmanship skills are his best skills overall.
After that, go to a church or a save statue and get your Litheness points refunded. What you’re going to want to do right off the bat is spend a handful of points in Litheness to unlock Fuddle Dance, the first skill in the Showmanship tree. It’s much better for Sylvando to use a dagger and shield and focus on Showmanship skills. Swords is terrible, so forget about that one immediately.
When Sylvando joins your party, he has 5 skill trees available: Knives, Swords, Whips, Litheness, and Showmanship.