I try to be an effective leader by not killing my employees...
Seriously though...
Be fair - don't play favorites.
Be honest.
Keep them informed. If you can give out information to your staff, do so.
Be cheerful in the face of change.
Make sure you know how to do the job of everyone under you. Not so you can do it yourself, or try and tell them how to do it better, but so you have a common understanding of what the job is.
Encourage, never demand.
Interact with your employees. A manager who stays in their office all day is not managing effectively.
Don’t use passive voice when talking face-to-face; it’s patronizing.
Be consistent.
And above all… have a sense of humor.