User Research and Heuristic Evaluation are the keystones to excellence in web delivered application design.
Heuristics are "rules of thumbs", or "best practice" guidelines. It has been proven statistically that expert interface designers can examine a site or application and identify upwards of 90% of its usability issues by systematically applying design heuristics.
Over the years Tristream has forged it's knowledge of best practices in the foundries of direct experience with Fortune 500 companies.
Tristream's Top 10 Web-Delivered Application Heuristics