1) I have a policy called "kiss your spouse when she leaves the house": meet her at the door, ask if you can help carry anything, giver her a kiss, and close the door so she doesn't have to fiddle with her keys. Reverse the process when she gets home.

2) It can help to have little moments where it's traditional to sneak a sexy kiss (empty elevators, car washes, whatever). And (unless you are a sex writer on Medium) it's not going to lead to immediate sex, it's a moment of stand-alone hotness. It's fun to be on an elevator and as the doors are closing realize you're alone.