To educate yourself about the normal appearance and habits of your reptile species: subscribe to hobby magazines, visit zoos and reptile shows, join a local reptile club, and refer to recent books that have good color illustrations. Nature programs on television often have excellent footage of animals in the wild. Observing your species of reptile, reading and speaking with experienced reptile keepers will greatly improve your ability to recognize a problem quickly. A good reptile veterinarian is also an invaluable source of current and practical advice.
For more information, please read Reptile Health - Knowing What is Normal.