Rule #1 - Be Yourself! A great way to drive yourself and others crazy is to follow trendy advice that tells you to take charge when entering a room by asserting your personality in a dazzling and impressive manner.
Use "power" handshakes by gripping like your hand is a vice. Then, in hypnotist fashion stare down the other person. NOT good advice! Instead, work at always being YOU at your best. Be a "what you see is what you get" type who never changes character from one situation to another. Be the same whether you're involved in an intimate conversation, giving a speech to a local service club, or on a job interview. Communicate with your whole being-your voice and gestures being in sync with your words.
In the Public Speaking arena don't send confusing signals to your audience by looking down at your shoes while telling them how happy you are to be there. Look happy - not angry, frightened or depressed. Visual cues will always outweigh verbiage to an audience. They can tell immediately if you're being honest with them.
Pay attention to your eyes. It's the same for one - on - one as it is for talking to a group-look at them. There's nothing more distracting than to have someone begin to speak to you while looking right at you and then within seconds their eyes wander out the window. When entering a room look around in a comfortable manner and smile-don't force yourself upon them - relax!
By practicing all of these ideas you'll, without a doubt, communicate a good impression during those first crucial moments.