There is really only one tool that you need for this, and that is your brain! So put away those expensive tools, and get ready to think!
So, ready to use that brain?
There may be few other optional tools that can help you along, especially if you are really stuck. Magazines, tv ads, radio ads, browsing at Walmart, etc. I would try to only use these if you're stuck.
The reason I say this is because the type of thinking that I am going to show you will help you get into the customer's mind; ads and products DON'T get you into the mind of a customer, it just shows you things that people buy. Products can help jump start, but it's not the most effective at helping you think like a customer.
So, ready to use that brain?