Magic is a touchy thing to begin. I suppose the first major question is religion.
What is your religion? Is it compatible with magic? Do you wish to change religions to a magical one or simply merge what you have? There is much debate on this topic, but here is my opinion: Most religions ban magic as evil and have severe penalties, either now, in the eternal, or both for practitioners of any form of magic. More than likely, your current religion will not mix with magic. Many practitioners have to break from their current belief system and form/join a comfortable hybrid religion. Also, the option of simply abandoning what you currently know as religion and radically changing your belief system is open. It rarely works, due to moral and emotional conflicts, but it is still an option.
The second major question confronting magicians is, “What is my nature?”. This question spawns many different answers. Some like aggressive magic to attack an adversary, or a friend’s adversary. Many use protective magic to shield themselves and their friends from the stormy blast of other magic. Many people abandon the idea of combative magic all together and opt for enchantments to ease the burdens of life on everybody, such as blessings and prosperity spells. Here are most of the major classes of magician (as far as I can tell, all spells can be accounted for within these castes):
White Magician – Expert of Protective and Healing Spells.
Black Magician – Expert of Destructive Spells.
Mage – Expert at Psychic and Mental Control, and Spells of Willpower.
Druid – Masters of Nature and Natural Forces.
Enchanter – Experts at Area Effect Magic (Curses/Blessings).
Diviner – Experts of Future and Fortune telling.
Conjurer – Experts at Summoning Spirits or Entities.
Healer – Experts at Manipulating and Sustaining Life Force.
Necromancer – Experts at Manipulating Death and the Dead.
Sorcerer – Freelance Offensive Casters of All Types; Mainly focused on black magic.
Wizard – Freelance Defensive Casters of All Types; Mainly focused on white magic.
Priest – Calls on God to defend them and to work with their situation as necessary.

Satanist – Calls on Satan to indulge their desires.
After deciding what you want (or, more accurately, what you are able to do), it is time to confront the third, and most difficult question of magic.
The third question of magic is the most difficult because of all the options it presents: What do you want? This is by far the most difficult. At this point the magician must decide how to shape their universe. Do you want money? Design a prosperity spell. Do you want power? Create a node. Do you want knowledge? Learn demon conjuration. Once you have the power, you must figure out how to use it. Wow! Enjoy figuring out the intrinsic of how to use abilities on your own.