Take Part in Daily Photo Themes
Engaging in daily photo themes on Google+ is a surefire way to get interaction with your images. Effectively you're engaging with smaller mini-communities of photographers, giving you a much greater chance at having your images seen by other users on Google+. The premise is simple: Include the appropriate hashtag to the post containing an image you're sharing, such as #MountainMonday (which should have a mountain within the frame of your image). Figure 8 shows a great example.
Figure 8 Ron Coscorrosa's submission for Mountain Monday.