There are many things that are the same as selling offline. But many are different. Unlike the offline world, a potential buyer does not get to see your work in person. They do not see you in person.
But that doesn't mean that selling art online is harder. In some ways it is easier. This is a very broad subject to cover in one sitting.
But if you remember to use the following tips you are guaranteed a leg up. Be completely honest about the work that you are presenting for online sales. An art purchase is a very emotional buy. It is almost at the same level as buying a house or a car. Of course the potential buyer has to feel an emotional attachment to the piece if they are going to purchase it- this is not the place to create that.
If a buyer is emotionally attached enough to the piece to buy it and then receives something that was not exactly as expected- your buyer will be unhappy and probably ask for their money back. If not I guarantee they will not be buying any additional art pieces from you. You can't risk this because someone who collects art is just that- a collector. Future purchases are highly probable. Make sure they know exactly what to expect. Be honest about condition, provenance, and artist background.
Be completely descriptive about your art for sale. Make sure that you have stated all of the important information about the piece. Give the art buyer as much information as possible about the piece. This will reduce the amount of questions and help qualify the potential buyer. These small but important facts will do a lot of the selling for you.
Make sure to include price, medium, size, type of paper/ canvas, framed/ unframed, subject matter, and date. Don't forget to include; your motivation for choosing this subject matter, what it means to you, challenges when working on your art, and why you have chosen to express these ideas in this manner. This is where you create an emotional attachment. An art buyer becomes attached as they begin to feel they understand the piece and the artist behind it. Make sure that you are able to accept credit cards for the purchase.
If a potential art buyer has to take the time log off their computer, pick up the phone, write a check, and then reach for an envelope you reduce your chances of finalizing the sale. Although they may still want the piece it is not hard for consumers to procrastinate as other things in their life need to be tended to also. The sale is lost. It is in your best interest to make the sale as easy as possible.
The only job the art buyer should complete is deciding which piece they cannot live with out. Believe me that is hard enough. Once they have decided on the purchase they must be allowed to pay for it immediately.
If you do not know how to do this you can easily accept credit cards through http://paypal.com it is free to sign up. Don't forget to include all documentation that goes with the purchased piece. Art documents have value and they also increase the value of the piece. On some level the buyer will view them as valuable as the piece itself.
These papers will be passed on with the piece and guarded the same as their insurance policies and bank statements. If possible be sure to include an artist statement, artist bio, press releases, promotional materials for you as an artist (post cards or brochures), history of the piece, and an appraisal statement for starters. Provide these to your customers in a folder so that they can easily be kept together and nicely displayed. Be sure to include contact information perhaps in the form of several business cards. Retain the contact information of the buyer so that you may contact them again in the future.
If the buyer liked you once, there are strong chances that they will buy from you again.
My vision is to even up the artist playing filed by making it possible to continue to feed their soul while making a living doing what they love. Every effort on this site is with that goal in mind. If you are interested in learning The Fine Art of Selling Art Online; roll up your sleeves and step inside. http://liqwidart.com