I've had the opportunity to work in organizations with waterfall as well as agile scrum process. Personally I love Agile and Lean UX as it is fast, iterative and collaborative. I involve some of the processes and methods mentioned below:
For every design to be successful it is quintessential to have a good understanding of the problem space and business goals. Depending on the access to the users, I do formal user research or gorilla studies to get quick understanding. I use analysis techniques to get insights into user needs. I often use this opportunity to evaluate some early direction in the design.
Product discovery, Value definition, Defining KPIs
Before rushing into designs, I look at the big picture of the problem. Without imposing the pragmatic constraints early on, I come up with scenarios for the optimal user experience. In case of multiple releases, this helps defining the direction that the product should go in across multiple releases.
UX research & analysis, Conceptual modeling, Usecases, stories & story boarding, Scenario building, Experience maps
Design, Validate and Iterate
Once the definition has been put on paper, I quickly iterate on designs to reach the defined goals. This is a fast paced and collaborative phase when I meet with stakeholders, fellow designers and users to produce and refine design ideas. The idea is to be quick and dirty on and keep refining. The phase usually ends when we reach consensus with the engineering, product teams, user experience teams and have validation from the users.
Iterative design, Workflow / task design, Rapid prototyping, Lo-Fi and Hi-Fi prototyping, Cognitive walkthroughs
For me, the design does not end with the creating and evaluating designs. I work with the engineering team through the development, evaluating the development progress, providing them assets and feedback. A good working knowledge of front-end technologies help me be an active participant in this phase.
Visual design, HTML5, CSS3 & jQuery, Web analytics
Working principles in design
I keep these principles handy to better work on projects:
Show early show often
Its always good to show your designs - as early and as often as you can. Its good to catch shortcomings in design early than late.
Ask a lot of questions
Most important questions are the seemingly silly ones. Asking question has opened up underlying issues more often than not.
Make mistakes and move on
It's said that the master has failed more times then the beginner has ever tried. I try to experiment, make mistakes move on quickly out of them.
Tell a story
Everything is a story to be told. I use stories to tell the user problems and product solutions.
I go broad before focusing on the details. This gives be a chance to unravel and explore ideas that would simplify the overall story for users.
Most importantly have fun with your colleagues while solving complex problems. I love what I do and have a lot of fun while doing it.