Think hard about your business, and what you want your website to generate. These are called action points, and should definitely be in your website design specification.
Action Points refer to one or more actions you want your visitors to do which in the end generates money to you. This include buying things, subscribing to your contents, telling their friends, or (for blogs and news sites) read more contents.
Prioritise your action points depending on their values, and present them strategically on the website design according to the priorities.
Know the common reading pattern to determine the screen real estate values ("The F Word"), and place the action points at the right place, starting from the most valuable ones.
I am quite disheartened to see a large number of website designs are being sold without even a single action point. An accommodation site with no reservation point, a car part supplier website without product list and prices or even a contact form, etc.
Think about your website as your shop. Imagine if you are not selling anything on your shop? Or if you put every items in your warehouse, what would your customers see/buy?