The way I come up with an idea is a strange yet simple process.
When pondering an idea or brainstorming a strategy, I first try to clear my mind of all other thoughts. Distractions are minimized as best they can be. A sip of water or other cool beverage is taken to symbolize this cleansing process.
Once the mind is clear and focussed, I begin the ideation process - usually by starting a word tree. I'll jot down a few words that relate to the subject. Maybe I'll put some related words branching off in a different tangent on another side of the page or board. After a solid twenty or thirty minutes, I may have a page covered in words, phrases and idioms relating to the topic/s at hand. A second sip of water or cool beverage is taken to keep the engine cool.
An imaginary, clear, upward-facing bowl begins to extend out from the back of my head. Above this bowl is an imaginary, wide net coated with slippery ooze. Looking up with my eyes to the left and right (which promotes left-brain right-brain cross communication), I begin to see ideas floating in the ether above me. One by one, I gently pluck these ideas (being careful not to damage them) and toss them in to the lubricated netting. These ideas, once caught, then slide down into the bowl and swirl around. Occasionally one or more ideas may connect or meld together before being sucked inside my head. My brain soaks these ideas up like a dry sponge. This makes the body fairly thirsty and a further sip of cool fluid is taken.
Throughout this process, the levels of confidence and self-esteem vary depending on how far in I am and how many ideas I have (and how many might be worth a second look).
This process is usually repeated again with a creative partner or team where we share our ideas and toss them up in the air while seated around a table. Our imaginary head bowls and nets are intertwined. The best ideas fall into this collective netting and make their way to the bottom of the bowl, blend together and plop down in a splattered mess on a page in the center of the table. After a flash of light, there is usually a gooey, pulsating lump. It is up to the team to work this new creation into a fully-formed, moulded and sculpted concept. And it is from this concept, when nurtured (and given a little water) that a campaign family of executions can be bred.