Being a sports fanatic is not going to be enough, in most cases, to get yourself a position in this competitive field. The ability to present information in an exciting, interesting, and memorable way is a talent that can be polished, but can't really be manufactured. People who have found success in theatre and public speaking seem to be better suited to this occupation. People who are comfortable in front of the camera, with an outgoing personality and a strong knowledge base for sporting events and commentary will find this field suitable, while the more reticent game fan might be more comfortable doing research and writing, working in the production end of broadcasting. This tends to be a fast-paced career with a high-energy atmosphere. Nights and weekends are practically a given in the sportscasting field, and some broadcasters that specialize in a particular sport that is played during a specific time of year might find this to be a seasonal occupation as well.
There are no hard-and-fast educational requirements in the industry, but a journalism degree, specializing in broadcasting, would be a good starting point for the prospective sportscaster. Having a strong knowledge of sports history and a broad base of game knowledge in general are also very important, but these things alone will not make up for a lack of broadcasting knowledge. Developing the experience, knowledge, and expertise to move up the ladder to bigger and better assignments make up a great deal of a typical sportscasting career arc.