Crikey CD, you must be ancient .....which is why of course you give such sage advice!!!
A business course is definitely a must.
In the short term, look within your network, you will have friends and family who can refer you to potential clients.
And your immediate locale, go to businesses that you use, see what they need, join local networking and business groups who will host breakfasts, lunches etc with guest speakers. Even offer your services as a speaker, your ME experience will make you interesting. Speak about security issues and counter measures.
Get a good lawyer, and a good accountant.
Have a decent business card, one that is traditional, and excellent quality, they are the first contact a potential client has with you and can say a lot. I starting using the Lux from moo.com. Bloody expensive but everyone I have ever handed one too has commented, it's a great icebreaker.