I cleaned houses a few years ago. I set up a flyer at the local grocery store. I never set it up as a business - i just told the people I called that I was a SAHM wanting to add to the household income. I also mentioned that I was not a professional cleaner and that I would clean their house first to see how long it would take me and then set the rate. The going rate around here was 15-20$/hour. I charged 15$ because I was new at it. I live in a rural area and when I went into the city to get a haircut, the hairdresser said that city rates are $45/hour!!! I also supplied all my cleaning materials other than mop and vaccuum.
As for how to clean - I found doing it room by room worked best and found my own "groove" when cleaning each house.
Rooms - Dust, tidy, vaccuum, make beds
Bathrooms - Wash, dust, vaccuum and mop
Kitchens - Dust, wipe cabinets, clean small appliances (microwave, toaster oven, coffe maker), wipe big appliances, wash dishes, clean sink, vaccuum and mop.
other stuff - wipe mirrors, wipe marks off windows (if they have dogs or small children), clean laundry room/sink.
The time it takes to clean a house varies. It all depends on how the house is set up, what kind of flooring they have and how cluttered and how many "knicknacks" a home has.
When I first started out I enjoyed cleaning the homes. But after a while I started to hate it. My kids were babies and it was very hard work. I would also come home feeling germy. But thats just me

I hope this works out for you!