If the funnel method doesn't appeal, work from the bottom up! Start with details, and work upwards.

For an example, we'll use Sage. Sage likes flowers - why?

Well, flowers remind them of relaxing in an open field, and they love nature and relaxation.

Why does that appeal to them? They're sleepy and tired all the time, and like peaceful environments for reading.

Start with one character trait and keep asking yourself 'Why?' until you get to the big stuff.