No offence Ian, I'm happy to discuss most aspects of biz, along the way I've made mistakes, tried to learn from them, I am surprised with your background you can't upsell on a regular basis, for me I encompassed the "add ons" along with reg window cleaning, priority was to get the solid base of regular customers first, but never turning away other work, as said you need to do long days, weekends, but you can still get in canvassing etc... But taking this work on allows you to get staff, they go off and do reg cleans, you pop out and knock off a conny roof, it's a fine balance, and fundamentally a good solid round is what's needed, but keep building as IMO a sole trader is a lifestyle career ( a very good one ) but the dangers of being on your own are illness, old age, family problems all of which will kill your income overnight.
Darran