Mate, So many times I have wished I started my biz when I was early 20's instead of leaving it until I was 35. I have just celebrated my business' 9th birthday on Saturday and it was the best decision I ever made.
As someone said earlier, get out and canvass and dont buy a round. before I started my biz my wife and I used to put £850 each into our joint account to pay for mortgage, bills, food, holiday fund etc etc so when I started my biz I knew that I needed to find that much regular work per month. I was out every night and got that figure by the end of the second month of canvassing. It was such a relief!
Another thing I did was I went out with other window cleaners to work free of charge just so I can gain experience. Two WFP guys and one trad. Found that very valuable.
Finally, keep every single receipt when you buy work stuff whether its uniform, shoes, to tools, van.
Best of luck and always ask on here if you are unsure of anything and best of luck to you and your family. Your boy is very lucky to have such a caring and responsible Dad.