Stands can be obtained 2 ways by getting shot by the bow and arrow (i'll explain the later) or by just havin it. Stands can be anythin from a book to a giant boat to a crazy astec lookin warrior. All stands have some kind of power they can use. The whole power thing sorda changed from series 3 to the later series. The stands in series 3 seemed to be well rounded and had multiple uses. Example: Heirophant Green could turn into tenticles, possess people, shoot emralds, and make giant web trap things. The series three stands like heirophant green could not be put into a specific power catogory they could just do a bunch of crazy stuff. Now from series 4 and on with the execption of the main heros all the stands seemed to have on use. They could be eaisily catagorized. The stand would have one real use and other than that it was worth less.
The bow and arrow: The bow and arrow is another one of those crazy JoJo ideas. The bow and arrow can force stands upon people. If you get hit by an arrow and live then you get a stand. A problem with the arrows is if it kills you then you don't get a stand....you die. Any way this was a big part of series 4 when people went around shootin people with the magical bow. It seems that the bow, although it is forceing a stand, seems to decide who deserves a stand by letteing them live. I think its sorda like you almost got a stand but you didnt have the fighting spirt but with the bows help you got one.
When people get a stand naturally they seem to deserve it. Most of those people have very strong wills and a strong fighting spirt (well execpt for holly). Its almost like something gives you a stand before you are born becuase you deserve it.
Well thats about it for now ill probably update this later.