I congratulate you on making your own way. You took a risk and it paid off. Now I try to clean but I just suck. Anyways, thanks for the thoughtful post. I have afriend who had to start a window cleaning business asap and he is doing alright.
A lot of times it has to do with equipment. We sucked at first but when we put everything we could into good equipment. Vacuums, for example. If you can get a SuperCoach backpack vacuum (ebay about $300 or so) this will do a much better job than push vacuums on SHORT rugs or hard-surface floors, stairs, under tables, and hard floors that you'll mop, etc. It will cut time vacuuming time in half. Also, if you can get an Oreck commercial for deeper rugs that will cut time. You can also speed up bathrooms if you put everything on a cart and move from one to the next with all your supplies. And the windows, if you suck on those, just go back about 20 minutes after you've done them (dry time) and take a very lightly damp newspaper and rub over the smears and that'll get rid of them.
Good luck with it and email me privately if you want, we've learned other tips like that to help us save time and do better work.