I started on the technical side, running a service department, and found that the problems worth fixing were in how it quoted and sold rather than how it repaired. Three months on sales and quoting lifted revenue and output with no extra payroll.
In 2001 I started my first company, an IT firm that grew from one customer to more than 120, then moved across into sales and marketing for good. In 2010 the New Zealand Government sent me to MIT Sloan's Entrepreneurship Development Program, and I have used what I learnt there in every role since.