I had a quick look at your site.
I have noticed you are not using meta tags efficiently enough.
You want to make each and every page on you site unique. In your case, nearly all pages have the same meta description, and some have the same keywords.
Here are the steps you should follow:
1. Each category on you site should be researched. Find the best keywords to describe your category. A good keyword will have sufficient monthly searches with little competition.
2. Once you have decided upon which keyword or keyword phrase best matches you needs, you should use it and its variations in you meta keywords, include the exact keywords in the title ( keep it bellow 70 characters) and in a unique description for that page ( bellow 156 characters)
You will also want to add some text when appropriate and include the keyword and its variation in it.
As you site is image based, make sure you use the same approach when uploading the images:
image name, tags ,title and description should include the main keyword you aim for , just make sure you use different text to each image and do not keyword stuff.
Do not over optimize you site, just make sure people and search engines can easily find what they're looking for.
Next, you want to form a link building strategy for the pages you want to promote.
Your goal is to have quality relevant sites in your niche pointing to you main url and your inner pages using the keywords you have selected and they're variants as anchor text.
You do that by submitting articles, videos, images, being active on forums and blogs and so on.
There's obviously much more to it, but I hope you got the point and hope I could help