How do you keep your knowledge of User Experience Design and Usability up to date and what are you looking at lately for inspirations?

Well, apply the standard practices of Design and Usability, there are many methods that you can do, but the only method that counts is the accuracy and credibility of the feedback that you receive, keep it simple, straight forward and concise. Apply your usability and UX Design response on accurate personas users, be more specific on your target audience, its not all size fits all Practice. and apply more of it, till you get a common trend in your answers that will help you make a decision. I recommend you read books, there are many in UX, such as "Don't make me think" for steve krug, and "UX for Projects" and you can check Lynda.com for Online courses on UX best practices and Responsive Design.