The worst thing about software development is to decide look and feel of the product. Your product wont sell if user doesnt like its look and feel. You need to give a hasan look and feel. hasan means good. So good look and feel is required. The best way to develop is to have good knowledge about your target user who will be using your product.
People simply loves microsoft product not only for performance, ease of use and security but also for its look and feel. So, Microsoft site will be best reference. You can have a good guide line here in Microsoft MSDN .