There are many ways to exude sincerity and self-confidence. The challenge is not necessarily in either showing sincerity or showing confidence but, rather, expressing both characteristics in a genuine manner all at the same time. Here are a few things to keep in mind when delivering that award-winning handshake.
Do not discriminate.
You have family, you have friends, and then you have everyone else. While a hug and a friendly kiss may work for some, you do not want to greet everyone with this particular style. This is where a friendly gesture in the form of a handshake will work for anyone you happen to meet. From the young child to the CEO, do not discriminate by giving a handshake to one or the other - give a handshake to all as it may come back to haunt you if you don't.
You will no doubt benefit from intentional practice as each and every time you shake another person's hand in another moment you can learn from. Take a moment to recall your posture, your facial expression and your attitude during that time. Your posture, whether standing or sitting, should be proper but not rigid. You're facial expression should be calm and welcoming. If you were deep in thought, you may return to a more serious look but be sure not to look like that when you make eye contact with the person you are shaking hands with. A sure sign of insincerity that many people pickup is when your attitude and your outward behavior are not congruent. If you are not in a good mood, it may be best to just hold off on shaking someone's hand for another time.
Get the technique.
Only when you've mastered being comfortable in shaking someone's hand should you move onto developing the various techniques associated with introducing yourself. A good place to start will be the firmness you apply during the handshake. Surely, you will want a comfortable handgrip but do not torque down so as to cut off anyone's circulation. Also, there are many studies where, while you are shaking with your right, you take your left hand and connect with the person's right hand, elbow, or arm for a more personal feel to the situation - I recommend that you reserve this for only persons with whom you are already acquainted with unless your mastery is beyond the common handshake.
Having the ability to shake hands with sincerity and confidence can have the ability to liven up any room. Alone with the ability to introduce yourself, I recommend practicing on remembering people's names - that's another topic of discussion. Shake away!