Basics of creating great user experiences
I'm flexible!
There is no single UX process that is best for every team. Many factors go into creating the right process that works for a specific company, product, or team, such as:
the size of the product team(s),
the development methodology in place (e.g. agile, lean, waterfall),
the technical architecture(s) in place,
the specific skillsets of the UX and product team members,
the company culture, and so on.
I have experience with many different environments and processes, so I'm very flexible in how I lead UX, customizing the process for the best possible fit, given the factors in play. Do you already have a UX process in place that you believe in? I'll adapt to it and move it forward. Do you need to build a UX process from scratch? I can do that too, in a way that is the most effective for your culture.
Below you'll find some basic philosophies and methods that form the foundational framework for making UX successful in a Lean/Agile environment.

UX Design is heavily iterative
The high-level process shown here will be repeated hundreds, or even thousands, of times in the design of a digital product. Short cycles and fast iteration over potential solutions, in a cadence that is in tune with development, provide the most efficient path to success.
Great UX lives at the intersection of user needs, business goals, and technical possibilities. Continuous prototyping and testing allow us to zero in on delightful solutions and find that sweet spot.

I practice Lean UX, which focuses on outcomes, not deliverables
Philosophies / Methodologies
User-Centered Design: Continuous User Research, Rapid Prototyping, and Usability Testing in the shortest cycles possible allow us to continually keep the user's needs at the center of our work.
Lean/Agile: Iterative, Evidence-Based Design that focuses on outcomes, not artifacts.
Mobile First & Responsive Design: For users, simplicity always wins, and Mobile First Design helps us tame complexity. Responsive Design allows us to provide great experience on all devices with a single codebase.
Accessibility (WCAG / a11y): Inclusive design increases product reach, allowing everyone to have a great experience regardless of their abilities.
Design Systems: Living Style Guides, Pattern Libraries, and UI Components provide consistency and accelerate time to market.

Iterate!
UX Activities
Planning and Strategy development ensure that we're building the right thing for the right people. There's no substitute for continuous user research.
Iteration, both in the Design Loop and the Implementation Loop shown here, is key to great UX design outcomes.
Adjunct activities, such as hiring UXers, cultivating a Design Thinking culture, developing Design Systems, and updating Strategy drive an organization's UX maturity forward, ultimately creating competitive advantage as our products become increasingly user-centered.

Design and Implementation Loops
Per-Sprint UX Activities
Here we see the basics of UX iteration in a Lean/Agile product development environment. In my years of experience, "just in time" design, where we design UX solutions no more than one or two sprints ahead of development's implementation provides the best mix of iteration and agility that moves the product forward effectively while syncing well with development. Designing too far ahead creates risk, especially that conditions will change and invalidate the research or business constraints upon which our design is based.
For upcoming development sprints, we work with product and development to understand the use cases or user stories that Product has prioritized. We then design and build prototypes, which are then usability tested and revised, iterating as quickly as possible to find the best solution.
For the current dev sprint, we implement in code the UX designs that are ready for the user stories that were selected for the sprint. For each iteration of the implemented code, we perform multiple UX tests, for responsiveness, browser compatibility, accessibility, and usability.