Interview users and observe them working in their environment. Establish a relationship for prototype evaluations. Gather data on user experience levels, goals, pain points, document as personas and scenarios.
Kick off collaboration with teammates by starting with wireframes. Capture engineering input, perform quick revisions and establish a preliminary plan with sketches, wireframes, and sitemaps.
Explore the technical medium and increase your expertise. Start early so you are not afraid to throw away prototypes. Usability test with users to get feedback. Iterations help to mature the design and the technology.
I use the term 'architect' in lieu of 'designer' to highlight my ability produce high fidelity prototypes, program, and consult on UI technologies. I've worked within Java, .Net, and Flash Builder projects in waterfall, iterative, and agile development processes.
I develop mostly in jQuery/jQuery Mobile with substantial experience using ActionScript 3.0. I have extensive experience with progressive enhancement and accessible design.