Have a plan; be wary of technology
1. Start with a plan
Just like blueprints in architecture, a properly executed plan shows you how the new site will function before it's built. It is far easier to move a wall during the planning stage, as opposed to an actual wall during the construction phase.
Those same principles apply to websites. Intense focus should be placed on a site's functionality and content before the more subjective design phase begins.
Below is a sample plan our agency prepares in the early stages of our web projects. The overall plan view shows every page in the website, focusing on navigation and sub-navigation.

2. Don't be seduced by technology
A website that is well thought out and easy to navigate will always outperform the latest technology in the long run. Hot technology features should be integrated only if they serve the needs of the site. Don't feel that you need to include the latest feature du jour just because everyone else is doing it. Forget about dancing babies and dazzling light shows.
In the end, it's the clarity and overall "stickiness" of the content and ease-of-use that will make the best impressions.