Too much exposure is just as bad as no exposure. An art dealer friend of mine asked me to create a website for him. When discussing what he wanted the site to look like, he was very specific on the size of the images and how many from each painter he wanted displayed. He was also very specific in asking me to watermark everything, not just for copyright laws but because, as he explained it: "The value of a painting can diminish quickly once its put on the web and easily accessible to the general public." To save yourself the same fate, display your work specifically in galleries, not just all over the place. Keep them in one place and refer all links to them instead of uploading them to every site. And make sure you watermark it!
Don't always put your best foot forward!
Just as in music, you could portray yourself as a "one hit wonder" if you constantly display a single piece that far excels your other work. I've often been advised that "surprising" a perspective buyer with a piece has a much better effect and allows the buyer to believe you are improving over previous work. Thus they would be more inclined to return to view future pieces.
Variety is the spice of life!
Showing a buyer you are a diverse artist often allows you to be viewed under multiple genres as well as allowing you to deviate from your previous works without compromising your integrity. This allows an artist to expand their studies, shows and explore more without putting anyone off. This does not mean you should compromise your style though! This is your signature and applying it to various genres only shows your strength in it.
Careful what you wish for!
Displaying your work is asking for criticism whether you realize it or not. Remember, not everyone that views it is going to like it. And not everyone that reviews it is going to be kind. You need to keep in mind where the criticism is coming from. If its from Joe Schmoe, don't take it personal. If its from a buyer, listen to what they have to say but always remember, personal tastes play a huge part in art critiquing. If its from another artist, view their work and see if they are in the same genre, caliber and/or medium you are. As an artist that works primarily with acrylics, I can offer very little to those that paint in oils. I can only offer how the piece looks to me, not any technical advice. Others may not feel the same and might offer unsolicited advice. When posting any pieces, you might think about adding specific descriptions, allowing the viewer some insight to the piece. I even post my study pieces specifically stating that is exactly what they are.
Network, network, network!
As a business consultant, I cannot give any better advice than networking. Art is a business and you are selling your wares to an open market. This means anyone that views your work is a potential buyer because there isn't a specific market group any artist's aim for. Networking allows other artists to view your work and possibly give you leads to buyers. But don't limit yourself to just art communities, blogs and sites! One of my most predominant buyers found me through my online game! An off topic discussion of art lead him to buying several pieces of mine and him showing them to others who bought other pieces from me. Get out there, display your wares and talk, talk, talk!
Now... here are a few links you might find interesting. If you have any you would like to add, please by all means, leave a comment with the link. These links are not limited to just painters or traditional artists, so please have a look and tell me how relevant you found them. If you build any profiles or already have one on any of the sites, let me know and I will send you my profile information as well.
Artist profile sites:
The Artist Network
Art for Show
Women Artists (sorry guys, you need to find your own site. Sexist I know, but I couldn't find a male equivalent)
My Art Space
World Artist Directory
Sites for selling artwork (these sites were picked because they had the most unusual way of presenting art for sale. I also thought they might inspire you to find unique ways to offer your art to the general public even if you don't use the sites.):
Thriving Ink (on myspace) - They create clothing from your artwork!
My Art Contest
mpRing - They sell your artwork as wallpaper on cell phones!
Artists Network (different than above link)
Information (copyright, business, marketing and more):
Art Space USA (This is a non-profit organization that offers space for artists and exhibits)
Americans for the Arts
Artists Rights Society
Art Rage - This is an extremely useful tool (with both a free version and a very inexpensive full version) to creating 'painted' images on your computer!
Your own ventures:
1) Start small: A quick search can tell you how to contact your local Art Council / Society.
2) Think Big: You can usually find various state and city websites with artist directories you can create profiles on. These sites usually list exhibits and shows with information on how to contact them to have your own work displayed.
3) Don't bother: Getting lost in a sea of other artists does you little good. When creating profiles, you can make one on every site, but unless that site has rank in search engines, its not going to benefit you.
4) READ! Make sure you understand what you are signing up for before uploading your images onto a website. Reading the fine print will allow you to determine if that site is genuinely looking out for your best interest as an artist. A LOT of sites do not protect you an any way, shape or form from other's stealing your work.
5) Copyright EVERYTHING! As an artist, you are protected under certain laws allowing you the ability to sign your name to your art and its copyrighted (to an extent! In court, you have to prove you are the original artist if you do not fully copyright your work and that is simply not as easy as showing a canvas with your initials). Don't put an image on the net without your name, logo, copyright information, initials, whatever identifies it as your original artwork.