Every image you post can have a target link attached to it. Anyone that clicks that image/link will go to your site, or wherever your link leads them to. So, it's all about the images you post, the titles/descriptions you use (which should be relevant to the image) and of course the domain/link you attach to the pin. They should all relate to each other.
The hard part...these days...is Pinterest ranking your images so that people see them. And therefore have a chance to click those links to get to your site. And as blackbeans said, engagement plays a big part in ranking. If the audience doesn't engage with your images, then Pinterest will drop your image impressions like a stone.
I know some may not agree, but one thing you can do to improve your impressions and engagement is to use idea pins. You can't attach a link to idea pins, but they are good for driving your impressions and engagement higher than normal pins would. So mix in idea pins with normal pins and see how it goes.
Hope that helps.