Research & Strategy... I'm someone who gets enthusiastic about diverse data points.  Melding design trend analysis with anecdotal market feedback and sales data is a beautiful act of both art and (dare I say) science.  Deeply understanding and clearly articulating the "why" is a habit.  I believe there is a fundamental dependance between insights and business growth - the greater your insights, the faster you'll grow.

Best practices I typically deploy:  market visits and customer feedback, design insight brainstorms, socioeconomic and STEEP trend research and analysis, design trend research and forecasting, portfolio benchmarking and competitive analysis (both direct and indirect industries), market surveying, sales data analysis, and informed intuition.