My first project came from a former coworker who moved to a new company. That's pretty much it.

Can't tell you any clever acquisition strategy. For this sort of work you need a critical mass of credibility and connections. The more companies you've worked at, the more people who can vouch for you from the inside. When you're in corpo, you are basically pre-selling your consulting pipeline, before you ever need it.

On a personal note, I quit that hustle, simply because I didn't enjoy having to prove myself every other day to new prospects. Especially since I've been a software engineer for 12 years already. Now just work on my own products that can speak for themselves.