Speak with Jesthenis Sunstriker - the Paladin class trainer - inside the Sunspire on Sunstrider Isle.
As you advance within your class, you will want to take advantage of the training that your class trainer can provide you. For young paladins here on Sunstrider Isle, your trainer is Jesthenis Sunstriker. Speak with Jesthenis and see what training he has available for you. The things he will teach do have a cost, so bring some coin with you.
Your trainer - as with all the trainers on Sunstrider Isle - is inside the Sunspire on the lower level.