I wouldn't treat a romantic scene any differently than any other scene. I would really say the biggest preparation was chewing gum and breath mints! For a kissing scene, it's all about the breath mints!

In fact we put so many things in our mouths we constantly have to be reminded what not to eat. Look at that little package of silicon gel that's inside your sneakers. It says DO NOT EAT for a reason. Somewhere sometime some genius bought a pair of sneakers and said Ooooh look. They give you free mints with the shoes

Which meant his only assets were one whiny imprisoned Goddess, one sort-of-girlfriend with a dagger, and Leo, who apparently thought he could defeat the armies of darkness with breath mints.

I wouldn't treat a romantic scene any differently than any other scene. I would really say the biggest preparation was chewing gum and breath mints! For a kissing scene it's all about the breath mints!