Understand what your individual strengths and skills are to utilize for creation
Create your own creativity system
Undertake a new hobby every few months to see what it feels like to learn something from scratch and create
Surround yourself with creative people
Actually intentionally study creativity
Visit different countries
Live in new places often
Make a group of people with similar interests, share thoughts and improvize
Be comfortable with a high "failure rate".
Get into the habit of creating thought experiments - ask "what if?"
eHow has a shorter list. It seems a little clearer as it has only six items.
Here are the first two: