Jakob Nielsen provides guidelines and a key word for evangelizing usability within your company.
The key word for early evangelism is to be opportunistic in allocating your scarce resources. You can’t follow the recommended usability process in all its glory because your organization lacks the commitment required. Instead of fighting windmills, go for the easy wins. Paradoxically, the more successful you are at evangelizing usability in your organization, the higher the likelihood that you'll have to change your strategy. The approach that takes your company from miserable usability to decent design is not the one you'll need to get from good to great. Typically, usability becomes "established" in a company without giving the usability group the power to fully own the total user experience. The usability group is often viewed as a service organization that supplies usability expertise to project teams at their managers' request. At this point, usability groups rarely have enough resources to supply all projects with the services they need to meet the recommended UCD process.A company progresses through a series of maturity levels as usability becomes more widely accepted in the organization and more tightly integrated with the development process.And that’s the key, being opportunity driven (and creative) instead of being resource driven.