If your truely serious about keeping sharks in a home aquaria.
The best way to start - is first research the various shark species that are generally available. Find out the true basic info on the species your interested in. And try to find the most accurate sources. Remember even the common "aquaria friendly species" such as bamboos, Coral Cats or Horns need plenty of swimming room.
Next ask people on public aquatic forums - Like MFK, who may have experience or practical knowledge about these species.
It's always best to stick with one of the more popular species as your first shark - as these are generally easier to get, as well as tend to be the most hardy. See what the requirements are for keeping these species. And it's okay to start with a smaller species - and work your way up to larger species. Pick a species that you will be happy in keeping - since it's possible you may be keeping that shark for 20 years or more.
While Scott Michael's book "Aquarium Sharks & Rays" may be a good book to start with for private aquarists. It has good basic info on the species, basic biology, health, and what is needed for a home shark or ray aquaria. But His tank sizes are IMO - way too small(to keep for it's entire life) for virtually the species he has listed. Realize that other books are out there for those interested in keeping sharks or rays.
Books such as the Elasmobranch Husbandary Manual - offer an great view of how to keep sharks or rays, although it's specifically geared toward Public Aquariums. But has lots of info that could also be helpful to a private aquarist.