If you want to sell through galleries, research your intended market thoroughly by visiting potential galleries, make a shortlist (and for goodness sake ensure they do sell the style/subject of painting you do!), attend their openings and meet the owner, inquire about showing them your paintings. Forget about being discovered by a wealthy art collector; you've more chance of winning the lottery (though, as with the lottery, if does occasionally happen). Don't turn up unannounced with your portfolio under your arm (how often do you buy something from a door-to-door salesman?)
Be honest with yourself when looking at galleries. Is you work truly up to standard, do you have an identifiable style or subject area, do you fit what the gallery sells, should you be approaching smaller galleries first?
If you're going to sell your paintings directly, allowing visitors to your studio, don't forget to check your household insurance (and lease/resident's agreement) allows for this kind of activity. Set up an easy-to-navigate website with an easily remembered name (URL). Begin compiling a mailing list (and check the spam laws where you live before you send out a mass email) and start advertising yourself by leaving cards or leaflets where potential buyers might see them. Start small and build up, e.g. by approaching local B&Bs, the tourism office.
Ensure everyone who buys a painting has your contact details (and a few business cards) as word of mouth is one of the most valuable marketing tools around. Sign your paintings so buyers can't 'forget' when asked who the artist was. Make sure you've always got some paintings you can sell, even if they're only small ones.
How to Create a Body of Work as an Artist
Tips on Titles for Paintings
The Ten Commandments of Art Pricing
Signing a Painting
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