Art on the walls can manifest itself in many ways...home shows, cafes & restaurants, galleries, art fairs, real estate open houses, art club membership shows, competitions, group shows, open studio events, and so on...
Probably the most important thing I can think of is determining your market. If your stuff is geared to the art fair market (generally smaller works that are easily transported and hung in booths and canopies), then it takes lots of planning, some investments in supplies, smaller, more affordable "versions" of your work. That, and asking around to those artists who do it for a living. It's great fun, however once you're moving along. Always meeting new people and almost always in the great outdoors. Lots of travleing, too, if you scale up your geographic participation.
If your work is destined for galleries, group shows, membership shows, then develop a mail list. One of the most important aspects of "dues paying" is keeping a well-organized and growing e-mail list of interested parties. Everytime you show anywhere, you call on those folks to come and see your work. Everytime you find yourself short for the electric bill, call on them for support and have another show. It's best, too, to keep the audience's eyes filled with newer stuff everytime you do show. Surely, it's usually not a bother to receive an e-mail from an artist wanting you to come look at their work. It's better than spam, for chrissakes. Certainly better than FWDs...
Some concerns to be aware of when showing anywhere: Insurance, cleanliness, visibility, accessibility, and how your work will be perceived by your potential collectors. Your work may be so sophisticated that having them in a smoke-filled bar may not only denegrate your work, but the smoke can damage the piece, not to mention make it smell in the new collector's home. Not to say ALL bars are bad. There are some here in Dallas whose curating is top notch and their A/C unit works well, so look at where you wish to show your work and go from there.
Be honest with your work, in that you should be critical of your technique and craftsmanship. If you notice something "not-quite-right" about your work, someone else will, too. fix it.
Showing anywhere is good for you. Don't expect to sell anything right away. Get it in your head that you will hope for the best, but expect the worst. I know that sounds contradictory, but if you're constantly expecting success right away, then disappointment can stifle further growth - career-wise, that is. All failures (if it don't kill ya) lead to success...eventually.
As I've said before here, the place isn't the best part about showing your work...it's your work that's the best thing about the place. So, feel free to open a room in your house for an impromptu gallery show. It's easy and you'll find your neighbors will be the first ones to buy pieces. Once they do, they'll keep coming back.
In addition, join arts groups related to your medium. Meet other artists doing your thing. Talk with them. Go to meetings. Enter your work. Some groups have a system of meetings, critiques, and contests. All good for the artists' soul...
Peace & Air Conditioning,
Kevin