There are a few ways to get into the business. You can be completely independent; creating, printing, marketing and distributing your own images. This is a worthy aspiration. You can also work with a publisher and have your work published by them so that the bulk of the financial responsibility rests of their shoulders and you receive a royalty based on sales. Both of these work, yet are vastly different. It's up to you to learn the difference and decide which direction to go in.
If you decide to publish your own work then it's a matter of making your images print ready as you will be responsible for selling them. Preparing your art for printing means cleaning it up through Photoshop to make sure colors are working, the digital files are clean and there is proper copyright notice included. Your digital files should be at least 10 megabytes but not much larger than 50 or 60. You may want to create the digital file so that the images can be printed in a variety of sizes.
Once you have cleaned your images and they are print ready you can upload them to user generated on-line galleries that will feature your work and sell it and you will receive a royalty. They will be the printer – all you have to do is add your images. Imagekind and Finerworks are two sites that offer this feature. If you decide to be entirely responsible for printing it then you will need to work with a printer who will give you a cost per print, decide with you on the paper quality and will be open to drop shipping to your customer. It is up to you to market your work. You can do this through blogs, Twitter, word of mouth, brick and mortar galleries and Facebook. It's a tough way to go but if you enjoy social web sites and marketing then this is all part of the fun. You reap the rewards of 100% of the profit.
If you decide that working with an art publisher is the direction to go then it's up to you to do the research into which publisher. You can attend tradeshows to meet them or gather information through internet searches. Once you have a list review their sites to see if the work they publish is similar in style to the kind of work you do. If they are a publisher of very traditional western art and your work is urban inspired and very digital then this is probably not a good match and you are wasting your time. Look for a good fit. Once you have found that fit you will need to find out who the product development manager is and contact them. They will want the quickest and easiest way to review your work. Try sending them either your web address or a photo sharing site like Flickr that can be a quick way to review it. If they reject it, don't take it personally…everyone gets rejected some time or another; just keep trying till you find one that fits. However if you have little success signing with a publisher then you may need to take an honest look at your art. No one wants to hear that their art isn't good enough however a publisher is making large investment in your art – they need to be reasonably certain that it will sell. If they don't feel good about it then they won't work with you.
Finally, do your research. Find out what the hottest trends are and try new artistic directions. Be bold and understand that making money from art is a good thing. You aren't compromising yourself if you earn money from it, you are making a living and being paid for something you are good at. Rejoice in that.