Selling canvas paintings can involve many steps and take a significant amount of time. While you complete these steps, you don't want to be toting around your actual paintings. Take some high quality pictures of your paintings and have them printed so that you can carry them around.
Create an account on a craftwork-selling website such as Etsy.com, where you can sell your work directly. Post the photos of your existing canvas work on the site, and you may sell your paintings directly. Even if this is not the case, some customers of the site may contact you for other painting commissions in the future.
Visit local coffeehouses or other establishments where wall paintings are common. Depending on the subject of your painting, you may find receptive buyers at any number of local businesses, or you may have to seek out a niche location to sell your work. Business owners are often excited to own original pieces of art and are frequent patrons of the arts.
If you don't manage to sell any work at local businesses, try donating some of your work to businesses such as hospitals. Having your art placed in one of these high traffic areas will act as free advertisement for your work.
Enter competitions. Any awards you obtain will raise your profile and help you sell your current work, or obtain new work.
Participate in exhibitions and shows. While the commissions charged by most exhibitions are steep, you'll be exposed to customers looking for art in advance, and art buyers often scout these shows for up-and-coming talent.