Pricing art is one of the most subjective commercial activities attempted. If you compare it to fashion, it can be argued that branded designers (like branded artists) can command a higher premium because of the history and reputation behind the name. But oftentimes an article of clothing’s price is also influenced by the quality of materials, hand vs. factory made, scarcity and uniqueness.
Original art can be judged (sometimes) by skill of execution; however, quality of materials is often a non-factor (or, on the opposite end, think of art made of garbage), and the vast majority is hand-made, scarce and unique. Needless to say, pricing art can be a challenge. The Guardian newspaper recently asked auctioneer Philip Hook what sells in the world of fine art.
First, if you are an artist whose work constitutes part of an artistic period/style deemed of increasing significance by the art world (e.g. German expressionists), or if you've had a major exhibition at a local, neighourhood gallery... like the Tate in London, your prices will increase. If you have a back-story that can be romanticized - like unhappy love affairs, consorting with models, madness (but not illness - god forbid! - which buyers associate with reduced quality), rebellious behaviour, convicted felonies - your price point increases. If you can die young before you can cash in on your greatest success, even better! High recognizability is valued (that's a Warhol!). Other tips to increase likelihood of selling are pretty women vs. gloomy, old men; sunny landscapes vs. gloomy; calm seas vs. rough; scenes of life vs. death; blue and red vs. other colours; and beautiful vs. ugly nudes. Condition and provenance (who has previously owned the work) will also factor. Finally, there is the question of "wallpower" - the visceral impact that makes people want to own it... kinda like Justice Stewart's definition of porn: "I know it when I see it."
There are tricks (methods) to valuing art, even by inexperienced collectors at the emerging artist level. Alan Bamberger in The Art of Buying Art goes into great detail about how to make an effective purchase. He reminds buyers that when purchasing a work of art, one does not buy an isolated item: one is buying a portion of an artist’s total output which has to be evaluated in terms of that output. This evaluation should involve familiarizing oneself with the artist’s total output, including talking to dealers, collectors and other experts, and looking for clues (awards, write-ups) of what the artist does best (think a Henri Moore sculpture vs. painting). The individual piece should be assessed for its physical (is it signed or reproduction) and executional (composition, technique, subject matter) originality, and whether the art is major or minor. (Major works are better composed, more original, more detailed, better executed, more complex and larger in size. Takes more time and effort to conceive. But don’t confuse major with good and minor with bad, or major with bigger and minor with smaller. The best examples of any artist’s work are referred to as “major” - Alan Bamberger.)
Perhaps the truest test of a piece's value, at least to you, is to compare it directly with other pieces of the same price range intended for the same purpose. A good reason to look forward to the launch of Mercartto.com.