Here are some random little facts that set the Sayians apart from other races like humans and stuff
Strength:::...
This is definatly not a suprise to anyone, Sayians have far more 'Ki'or 'Chi' than ordinary beings and have learned to master it perfectly. According to Japanese culture everybody has a certain amout of life energy and it's just a matter of what you do with it, it is believed that with the right methods everybody can become as strong as they want. I think this is what the Sayians abilty is based on.
Their strength also increases after every fight, the more they're injured the stronger they get after they're healed again.
Tail:::...
Originally, every Sayian has a tail which, if the Sayian is not strong enough, can be extremely sensative. Vegeta's tail got cut off in his first fight with Goku, whose tail was cut off when he was a little boy. The Sayians take great pride in their tail and it is said that it is the source of their true power (Oozaru) and that it makes them more agressive.
In many Fanfic's it is told that the tail can be used to 'arouse' a Sayian o.O;; But this is never confirmed in the series.
Oozaru:::...
When a Sayina still has his/her tail, and they look into a full moon they will transform into a giant ape and their strength increases dramatically, that is why this form is also called, their true power. If the Sayian is strong enough and has had enough practice, they are able to remain in controll in this form and are even able to speak. This is why Vegeta could talk to Goku after he transformed and Gohan just went crazy when this happened to him.
Food:::...
Sayians tend to eat enormous amounts of food, as we can clearly see in DBZ at the martial arts tournament when Vegeta, Goku, Goten and Trunks have a serious pig-out while the rest of the Z-gang eat far less. It is never clearly explained why they do this, though...