My best definitions of some magical terms.

Magic


Dion Fortune, a leader in the original Golden Dawn and one of the most important Hermetic mages of the past century defined it as "Causing change in consciousness in accordance with will." Magic typically involves manipulating the life force (what Chinese and Japanese martial artists call chi or ki and Jedi call "the Force," the Hebrew word is ruach and my Druid tradition calls it Nwyfre.) It is typically done either through imagination/visualization, physical movement (eg. dance, martial arts), or using materials that are naturally charged with certain qualities of Nwyfre (eg. Juniper bushes are said to keep thieves away and elm trees are said to attract Faeries); combined with intent. Other plants, animals and minerals have their own effects and properties.)
The effects can be enhanced by ritual, by music and by timing the work to days when the spiritus mundi or general nwyfre of the earth are strong in certain qualities. One can also enchant (literally: to put a song in something) certain objects or places to help them in their work or to have a long term effect without needing to work magic every time. One might enchant a stone in their garden to increase productivity or prepare a satchel of herbs and minerals and keep it where they practice a musical instrument to increase the rate of improvement. 
However, the one thing that must not be neglected if one wants to learn magic is regular practice, just like if one wants to be an artist, they have to practice. For this reason, many mages say that all human activities, without exception, are forms of magic.


Occult


Literally means hidden or unseen. Occult typically refers to any activity taught only to those who have been initiated. In a general sense, it includes groups like the Freemasons or Odd Fellows.


Sorcery


The only kind of magic prohibited in restoration scripture. It refers to powers derived from evil entities (eg. Satan) or evil acts (eg. involuntary human sacrifice or torture of any living being.) Much of what Alister Crowley did and virtually anything promoted by Anton LaVey qualifies.. Sorcery can also refer to claiming magical abilities, either pretend or real, in order to deceive and get money, power, etc. Goetia is a type of sorcery under the literal definition of invoking evil entities. However, it can also involve improving psychological health by dealing with ones shadow side or personal demons (ie. damaged parts of the psyche.)


Black Magic


Any act involving sorcery or magic for evil purposes. Black magic always burns it's caster. Curses always rebound. However, magic for the purpose of ensuring a criminal will be caught, for example, is not black magic unless motivations are evil. 


Hope this helps.


Yours under the theoretical oaks,
Nathair /|\