My classes are usually organized like this:
T-Beam-Md-1a (Terran, beam-equipped, medium, model 1 mark a)
T-Troop-2b (Terran, troop-carrying, model 2 mark

and so forth. I name all the ships in a class after common themes, such as:
Jewels (Ruby, Tourmaline, Amber)
Battles (Trafalgar, Vittoria, Sedan, Shiloh)
Leaders (Grant, Nelson, Graf Spee, Davout, Friedrich der Grosse, Scipio Africanus)
Gods & Heroes (Hercules, Ajax, Daedalus)
Monsters (Minotaur, Chimera, Poltergeist, Vampire)
Predators (Lion, Barracuda, Python, Raptor)
Constellations (Andromeda, Draco, Scorpio, Bootes)
Heroics: (Invincible, Superb, Valiant, Constitution, Dauntless, Intrepid)