If you want consistent sales, its not as simple as putting your art in front of "people". You have to figure out who your market is. Who is it that will identify with your art enough to pay their hard earned money for some art for the wall that they don't really need.
The answer to that question is different for every artist, and can be different for different things within the artists portfolio. Until you can identify that market for a given image, or a given group of images, any marketing you do will tend to be scattered, and relatively ineffective. The best marketing is targeted marketing, but you have to know your target before you can hit it. Then you can target via social media, face to face marketing, internet ad campaigns, etc.
In my opinion, the watermark present on your images will discourage sales as well, but that can be a touchy issue on here and for some artists.