You have to have a rough idea of what that particular sport is all about, how much a game lasts and the basic rules. It is possible to ride on luck but this normally doesn't last. Gather as much as you can because research becomes a part of every gambler.It is possible to walk into a betting shop or go to a betting site and bet on any sport. It just isn't likely that you will win, as you would be relying entirely on luck rather than making an informed bet. If you really don't know anything about the sport and want to bet on it, reading the papers and seeing what the commentators think might help you choose who to bet on. If they think one side has an edge, there has to be a reason why.