You know it when you see it. Leaders that command attention and respect. Most often they are not shouters and screamers but have clear and articulate communications. The inspire people to action, the infuse hope, they have an agenda that bigger than themselves.

Obama!

We are know when executives don't have presence. They simply are not believable. Your instinct is to not trust them. They seem to have their own agenda.

Bush!

Some people are born with this but for most of us it is a learned skill. 

Vertical, open, grounded, confident where your body matches the words you speak.

Obama!