If you are an officer of your party, get out and pound the pavement. Lead by example. You took the responsibility, now use it. If you aren't an officer, you still can lead by example. Your goals should be outreach and name-recognition.
Registration is just the gravy.
If a Democrat wants to register at your table, do it with a smile. Same for Repubs, Greens, etc. Give them some material if they'll take it and thank them. Maybe they'll read something they like and change their mind. Maybe in a couple of years, they'll be looking for a political alternative and they'll remember how friendly those Libertarians were.