Non- Dragon Classes
Horizons is a Class-Based game, so you'll need to pick a Combat Class and a Crafting class. Don't worry about making a secondary crafting character - crafting and combat are totally different entities. Both crafting and combat disciplines have several classes available as soon as you start. As you level, you will be eligible to join different prestige classes. Each class has its own special perks, most of which I have listed for your convenience, as well as where each class's trainers can be found.
eventually a class guide written by a knowledgeable Paladin.... but that might not be for a while!
You can find more about Dragon Classes Here.
Need a Trainer? Look Here!