Type O
People with the Type O blood group, are said to be creative, confident and quite popular, they enjoy being the center of attention. Type O’s are also outgoing and very social, though mostly initiators, they may never get to finish what they start.

Type A
People with the Type A blood group, are said to be very trustful, honest and conscientious to a fault. Type A’s are also known to be perfectionists, they might seem outwardly calm but tend to have balls of nerves within. Type A are also artistic and are sometimes shy and sensitive too.

Type B
People with Type B blood group, are strong willed, goal oriented, they always finish whatever they start, whether in perfect timing or in excellent fashion. People with Type B blood group, always seem to find their own way in life.

Type AB
Those with a Type AB blood group, are an interesting lot indeed, though they are trustworthy and honest, its being said that they seem to have a split personality! Type AB blood group also like helping people, they are outgoing and confident but they can also be shy too.

Compatibility by Blood Groups
A is said to be most compatible with A and AB

B is said to be most compatible with B and AB

AB is said to be most compatible with AB, B, A and O

O is said to be most compatible with O, and AB

(Source: bellaonline.com)