Also remember that body language conveys a lot of respect or lack thereof. If you wish to be respectful, when greeting others there is a small downward nod of the head that is used as almost a mini-bow, when in passing, or to people one knows well.
If you are greeting someone you should be very respectful to, you must do the full bow. Women will keep their hands together toward the inside of their legs when bowing and men will keep their hands to their sides. If you need to be very respectful toward someone, your bow must be more inclined than theirs. Most do not bow at a full 90 degree angle as it is not comfortable. However, your bow, normally should at least be comparable to that of the person you are greeting. Sometimes people will bow multiple times. Just go with the flow of your counterpart.
Today, many Japanese also shake hands, but there are still those who are not comfortable with this custom yet. Unless dating, you will almost never see the Japanese greet with a hug or kiss on the cheek. Displays of affection are more reserved and can put people off in the wrong setting or situation.