Spellcasting 101: Practitioners of Arcane Magic (Part 1)

As noted there are various forms of magic, and likewise various forms of spellcasters.
Most notably the master of the arcane magics is the Wizard. Historically speaking though, the wizard is not the first practitioner of magic as that title most often falls to the Sorcerer.

The Wizard
A wizard is an individual, through study and research, who is able to unlock the secrets and practice of magic.
Such individuals are of a scholarly nature and follow a very analytic view of magic. They know that magic itself follows certain rules and thus through the manipulation of words of power, symbolic materials, and movements they are able to cast spells. They also have tendency to to be considered bookwise, as through the practice of magic requires learning of a variety of subject from basic alchemy, ancient history, reading & writing, art, herbal lore, cooking, geography, myths & legends, etc.
In most societies, an individual who is considered a person quick of wit and intelligence is most suited to become a wizard. Most are taken at a young age an entered in either a school of magic or apprenticed under an established wizard. Very few are self taught, sometimes having access to arcane documents or being coached by a spellcasting being.
Depending on how the wizard was taught; 1) They can memorize a certain number of spells per day (Standard D&D) that they can cast, 2) focus on an effect they want to cast (skill check), or 3) Cast a number of studied spells (spell points). It is a common misconception that wizard's forget the spells that they cast and must study them again. The main reason why a wizard must spend a number of hours to prepare their spells is mainly to refresh what selection of spells they can cast [The main benefit of being a wizard is the ability to learn and cast any number of spells!)


The Sorcerer
A Sorcerer is an individual who has a innate ability to cast magic. This is mostly likely due a biological influence such as familial bloodlines (magical/planar creature in their ancestor) or from exposure to some sort of magical/planar environment or creature. They can come from any walk of life an usually manifest their abilities at a young age. Usually they display powers that are categorized by ancestry or exposure (ability to cast fire spells may stem from the exposure to plane of fire or a set of spells cast by dragon may indicate a dragon ancestor). They usually discover their abilities on their own.
Sorcerers were mostly like one of the first to practice arcane magic, as it was an innate part of their nature.
As other saw their abilities, this most likely started the study on how to access that power and thus wizardry was born. Sadly most are shunned or feared, as individuals with strange powers. Most sorcerers usually keep their abilities hidden and attempt to use their powers in more subtle ways.

Unlike a wizard, a sorcerer is limited to the numbers of spells they are attuned too. Their one benefit is that they can cast spells more freely (in the sense of more spells per day). If they are fortunate enough, they can find other sorcerers who can help them discover spell they are attuned to. Some even go on a quest to discover their ancestral natures and learn from the creatures whom they share a blood bond with.

The Warlock
Some people want power quickly, others lack the innate ability to even practice magic, so the warlock offers those that path to attain powerful magics quickly (although there are a few rare individual who are born with natural ability). A warlock is an individual who has been infused with a magical abilities. They are living batteries of eldritch power who through the force of their will can achieve a number of mystical abilities.
Most notably, Warlocks have the ability to emanate eldritch bolts of power. This energy is often used to empower other abilities. Unlike wizards and sorcerers they can only achieve a minute number of effects, but can do so an unlimited amount of times.
Sadly Warlocks are dependent on their patrons for instruction, or must dig through magical research to find methods to access their power.