One of the social media I use to promote my portfolio is Google Plus.
Before starting to promote Dreamstime images there, I followed and built followers. Commented on other's posts, posted here and there, basically had fun while making connections and learning.
- Connect with other's content by commenting or plusing if you like it. Probably they will do the same for you. Criticize honestly when someone asks for critiques.
- Ask to be included in circle shares of your interest.
- Do not re-share everything you see from other's stream, unless it is important to you or you feel you really want to. Daily re-sharing other's content will make your followers uncircle you. It is boring. People want content YOU make. Otherwise, they would be following others.
-Be careful with the amount of daily posts. I post publicly one ore two messages daily, and some days I don't post.
-Share publicly your posts with links to your images on Dreamstime.
-Do not use the notify option. It will scare your followers away if you abuse this option.
It is easy to post your images with a link back to your image in Dreamstime.
-Copy the referral link from your image.
-On the "share news" box, paste it.
-Wait until you see the thumbnail and info retrieved from Dreamstime.
-Delete the link you have just pasted and write there what you want. I like to hash-tag it with a relevant theme for the day. It will increase visibility even for non-followers. It makes your post searchable by tag.
-Make sure it is posted to public (not for some closed circles). That way anyone on the web can see them.
-Hit share and it is posted.
Some more general tips if you really want the link to be noticed:
-The day of the week and the time you post your message will affect views and interaction. Weekends are slower. The time of the day depends on where you are in the world, and the audience you want to target, as the world is round, of course. There are some tool to help you with that, like CircleCount.
-If you have pluses but don't have comments, make it go up again by thanking the pluses (do not abuse this feature).
-If you have comments, wait some minutes to reply. It will make it go up twice in a set space of time, instead of going up once.
If you have a considerable amount of people following you, make a test. Before posting the link, check what is the amount of visits you have on that image, at Dreamstime. Check back an hour after, or even less. You will notice a really good bump on views. I had sometimes 20-30 views in minutes on a non indexed new image ( so I know the visitors came from Google+ ).
I'm not sure how it will impact the position of your images on google search, or even Dreamstime.com positioning, but I think it can do more good than bad.
On a final note, do it with pleasure. If you are doing it by obligation, go take some shoots or draw something instead. Feel good about your work.