Lateral thinking is a skill that atrophies without deliberate practice. Freelancers who work across varied briefs are well-positioned to build it, but only if they use the right resources consistently.
Books that reward slow reading
Edward de Bono's Lateral Thinking remains the clearest entry point. It is not a quick read, but working through one chapter per week between projects compounds over months. Roger von Oech's A Whack on the Side of the Head is shorter and more practical for generating ideas on demand.
Card decks as thinking prompts
IDEO's Method Cards and the Oblique Strategies deck by Brian Eno are both worth owning physically. Pulling a random card before starting a brief forces you to approach the problem from an unexpected angle, which often surfaces ideas that direct brainstorming misses entirely.
Online tools for structured randomness
Random Word Generator and Thinkpak's digital version both introduce constraints that push thinking sideways. Setting a 15-minute timer with a random prompt before opening a client brief has a measurable effect on the variety of initial concepts you produce.
None of these resources replace experience, but they reduce the time spent staring at a blank document.