From: Top 10: Ways To Show Confidence With Body Language by Andy Moore
Don't put your hands in your pockets.
Don't cross your arms.
Stand up straight
Don't look down.
Don't be afraid to smile
He also advises you to feel free to touch people. I would say only if it is a perfectly natural thing for you to do. If it's forced it's repulsive.
This reminds me of people who use your name more than they have to because they were told that this is what you want to hear. It's odd and disconcerting. It makes you not want to trust them.
The same is true of smiling. He advises you to smile. Fine if you want to but don't force it. You see politicians forcing themselves to smile when they speak to the media. It's incongruous and repulsive.