The cornerstone of SEO is having great quality content matching what your potential customers are searching for. I can’t emphasise that enough,  neither can Google, Bing and the other search engines. If you can’t find the time to research and add new content, then you are missing a huge opportunity and crippling your online business potential.

Find what people are searching for by using Google’s keyword research tool: https://adwords.google.com/o/KeywordTool

Or Bing’s keyword research tool: http://www.bing.com/toolbox/keywords

Even if you’ve done research previously,  take some time out to hunt for new ideas. 

TIP 1: In Google’s tool ensure you have phrase not broad match selected.

TIP 2: Don’t bother with the Bing tool, it is totally useless!