There are many many ways in which creativity can be developed, enhanced, and (perhaps most importantly in creative businesses) supported. I love the Disney strategy which separates the processes of creativity into 3 different spaces, the Dreamer, Critic and Realist. Each space has an equal contribution to make to the end creative product but its important not to jump too quickly from one to the next. The 'Dreaming' or brainstorming part of creativity is essential, and can't be tamed too quickly by realism, but if you ignore the audience or client (represented by the 'Critic), or fail to meet your deadlines or notice spiralling costs (Realist) entire projects can fall apart.
The Artist's Way is a bit of an old classic, but Julia Cameron's techniques are spot on in terms of unblocking and supporting creativity. I especially like her 'Morning Pages' (writing 3 pages long hand each morning, both as a brain dump and a means of training the mind to create on tap), and Artist dates, or the idea that you have to feed creativity with new images and ideas and experiences (which she calls 'filling the well').
Supporting creativity is also about improving confidence, as the quickest route to a creative block can be self-doubt or criticism.
I spend a lot of time writing about this stuff, if you are interested, check out my Creative Alchemy blog:
http://creativealchemy.typepad.com/creative_alchemy//