Sketch - "..because of the limitations of today's available technology, brainstorming should never be done digitally; it should be done with paper, pencils, pens, markers, and possibly whiteboards and sticky notes."
Doesn't have to be limited to designers only. All othere stakeholders should participate.
"Rules" of brainstorming:
There are no bad ideas.
Don't spend a lot of time on any one idea.
Use the whole room.
Start with a warm-up exercise - association game, mind maps. Point is to get brains, hands, and mouths engaged.
Set aside a fixed amount of time. Allow breaks. Ideal to spread brainstorming over several days.
Set aside most of what you know about the technical, user, or business constraints.
Focus points to brainstorm around:
Pain Points: part of the process or activity is problematic or difficult.
Opportunities: known places for innovation
Process Moments: known steps in the activity
Personas: focusing on addressing the direct expectations, motivations, and behaviors of one particular persona.
Metaphors: sometimes, the oddest metaphors will uncover a previously unthought-of direction for the design.
Brainstorming techniques for interaction designers:
Brainwriting: one person writes down or sketches the beginning of an idea. Others continue the idea one by one.
Break the Rules: figure out how to break the constraints.
Force Fit: distilling the problem down to two words that are in opposition, ex "intense peace."
Poetry: reduce the problem down to a short poem. Makes you figure out what is most important.
Questioning: start with a very general concept and keep asking two questions: how and why.
Laddering: moving "up" to a level of abstraction or moving "down" to something concrete
Swiping: stealing the best ideas from another field or domain.
Bizarro World: inverting everything: opposite product, good is bad..
Organizing the concepts: cluster, name, and sort all the ideas you've created so that it is easy to examine and discuss them.
"Mantras", "a set of phrases designed to help guide design decisions throughout the remainder of the design process - and even beyond, after the product launches."
Almost as design requirements, except they are general statements that should apply across the project. If you can't apply it to more than one feature, it's probably a requirement, not a principle.
Design principles are a combination of:
What is known about the users, the context of use, and the design strategy.
The best ideas that emerged from brainstorming.
What the designer thinks is necessary for a successful project
The best design principles are:
Pithy: a short phrase.
Memorable: funny, witty, and provocative statements
Cross-feature: should be applicable across the product
Specific: easy to Use is not a design principle.
A differentiator: if they can be applied to a competitor, then they probably aren't specific enough.
Non-conflicting: with each other
You can use design principles as a measuring stick against the concepts you've generated to see which ones best fit.