Be one, become one, use one.
Take time to help your producers (the internal and external funders and sponsors who underwrite and drive the project) discover and understand the fullness and complexity of the value relationships. Most important to the eventual end clients is that they get real value. If it's valuable to them, it must be valuable to the producers and the enterprises they represent. Understand the full economics - time, people, resources, funds. Account for everything. Account for the future. Account for change, constant change.
As a design professional practicing in the web, get out of the box of your own area of expertise and practice. In addition to getting wider primary expertise, get familiar with the planning and project management paradigms and methods of the various disciplines. Make a list - then make it twice as long and twice as detailed - and pursue it vigorously.
Deliver usable value. Designing for experience will make it possible to craft rich, integrated services that will fulfull the promise of usable value. A design professional can convey an experience at many levels and in many ways. Differentiate the service in its market -- in the way you drive traffic to it, in the ways different visitors 'consume' your service. Manage audience expectations. This is about more than just configurable and context-sensitive content; more than about registrations. Look outside your central service design to put in place an environment that helps your consumers transfer the value to their environments. To do this you may need to influence and change other consumer dynamics and behaviors (such as behaviors they might employ when they aren't actively consuming your services - before and after using your services). This, in turn, might require (gasp) written materials, in-person training, video; it might involve an entire value chain of the consumer.
Reject rule-based pet peeve pontification. These rules are the building codes of the web and their proponents the building inspectors. Novice designers, the putative beneficiaries, are not equiped to resolve the confusion and conflict resulting from such practices. Further, such practices lead to de facto standards and reduced innovation. What counts is the entire system in which the design lives - evolving, dynamic, non-linear, universal, infinite. Suggest - demand - changes to judging practices and to the communications of the results. Then participate. Be a judge.
The vitality and viability of the web depends on this. Learn why this is so; be prepared to educate others. Those producers who balk at this get the results they deserve. If you blink have a good reason.
As a skilled design professional, push, impatiently, and without deference, the computer science and technical professionals to engineer and implement the services and components you need. Get the email addresses of the consortia and committees and developers; and of the key systems managers related to 'your' projects. Be vocal and persistent. Here the rules are simple -- (a) assume that you are right; (b) be willing to prove it; (c) never rest.
After you've done all the above, forget about the 'right' rules. Is content king? Such tautologies are useless. Should you avoid frames, avoid big pictures, avoid decoration, avoid plug-ins, or avoid segregating visitors? Or is it the reverse? Avoid these creativity substitutes. Just Design. Use your design expertise to extract from the drizzle of whining criticism those gems that will help you explore and fail; learn and improve.
If you fail in the prior nine rules, it doesn't matter if you used the 'right' type of interface or information structure. The 'right' rule critics, the building inspectors, may think your design a success, but the real clients won't.