Simplicity is the key to an effective website design and development.
From a design (User Interface) stand point – website design should be smooth in terms if navigation. A user should always know where s/he is in the website – breadcrumb trail plays a very helpful role in this regard. From visual standpoint, shadows and gradient work should be avoided and simple flat buttons are preferred.
From a development perspective – the website should adhere to the latest web standards. Being responsive web development is crucial for a website now as more and more handheld devices are in use. Responsive websites give use an optimized experience based on the screen size.