I took a quick look and here’s some general tips:
Add more content to the category pages. Use the main keywords, longtails, variations and pluralisations in the copy.
Don’t target the same keyword(s) with multiple pages. I would probably reduce the number of sub-categories to just two; tables (including sets) and accessories (cups and balls).
Create pages for popular longtails, such as ”beer pong rules” (and make sure it’s the BEST page for that keyword).
Publish articles about related topics (party games, etc.) on external sites with relevant, contextual links back to your site (and other relevant sites).
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