User-Defined
One thought that can often be forgotten is who the end user is going to be. Of course, there is the client, but does the client have clients/users of its own and are they the ones that will mainly be using the site? For this reason, it is important to test outside of the company and test the site with people who are not familiar with it. It's the end users' needs and effects that need to be taken into account.
Site Maps
An important step after finding out who the site is meant is site maps. Not only does this help ensure that all the necessary elements/components are shown on the page, but it also can help simplify the page for the users. Site mapping can also help avoid errors and create a smoother site.
Planning the Site
One needs to keep the clients in the loop and include the client in the planning process. Knowing who you are designing for, who will be using the actual site, is how one can create a more effective site. The budget the client gives is what gives you the creative limit for the site. Also to be considered is the technology. It needs to be a stable hosting site that is easily accessible for the client. Lastly, the site needs to be able to last in the future.