(1) There is no one correct way to model a domain-there are always viable alternatives. The best solution almost always depends on the application that you have in mind and the extensions that you anticipate. (2) Ontology development is necessarily an iterative process. (3) Concepts in the ontology should be close to objects (physical or logical) and relationships in your domain of interest. These are most likely to be nouns (objects) or verbs (relationships) in sentences that describe your domain.

[by Noy and McGuinness (2001)]