There are probably as many definitions of the word "artist" as there are of art. And of course the "duh" definition would be, that person who makes art. If one wishes to go beyond that, there is a nice little thicket one must transverse between a definition that is on the one hand so narrow that it eliminates creative individuals who are in fact artists in the non-traditional sense of the word; and on the other hand, a definition so broad that it becoming practically meaningless, as in the case, for instance, of anyone who ever collaborated in "creating" a baby. And then there is the problem injected by the performing arts wherein all actors, singers, and musicians are called "artists" whether they merely sing or play (create?) music, or a dramatic role, or are involved in composing the work. To me, the latter seems a more apt definition in the original sense of the word. On the other hand, there are very many painters who also call themselves artists who are very much like singers, actors, and musicians in that they tend (often without realising it) to "play" that art that others have "written" sometime in the past. Are these individuals "performing" artists? Maybe it's more than a thicket...something on the order of a quagmire, perhaps.
Though it's not perfect, I kind of like the word "decider." An artist decides things. A performing artist follows the deciding artist whether in the visual arts or any of the other fine arts. The follower may stray a bit in interpreting what the decider has decreed but it's questionable whether that makes him or her an "artist" or merely an interpreter. Okay, now that we've slogged through that, what does the artist decide? Well, if you've studied journalism, the same guidelines apply, though in a somewhat different hierarchy perhaps. First comes the hardest one--what. What? What to do? Organic or inorganic? Plant or animal? Landscape or still life? Human or inhuman? The "what" question also involves the artist deciding what medium to use. The second decision is no less difficult, though it's often somewhat foredrawn by the artist's accumulated skills--how. Representational or non? Realistic or impressionistic or expressionistic? At the "how" level comes also, how big. And of course "how" is a technical question as well, pertaining to how tightly or loosely the work is to be rendered.
The other three journalistic points are less relevant to the work at hand. The "who" having only to do with figurative or portrait painters; the "when" more of a scheduling problem than anything else; and the "where" contingent upon size of the work being contemplated and the artist having carved out a suitable working environment. And finally comes "Why." Business or personal? Decorative or functional? To learn or to demonstrate learning? These are the big decisions. Once the work is underway, there is a seemingly endless sequence of little decisions (and some not so little) that the artist must make and (for the most part) make wisely if the creation is to "succeed." Not every decision must be the right one, but even a short string of bad decisions, especially if unrecognised, can wreck a work. Fortunately, in art as in life, there are few irrevocable decisions, until the final judgement when the maker says "finished." At that point, comes the moral and religious aspect of the creative process. Is the piece destined for salvation or has it gone to hell?