I tried mowing for other people to "make some extra money" but couldn't charge enough to make any extra. I figured $50 per hour for actual cutting time, which didn't include a charge for hauling the tractor/cutter to the site. What do you figure you need for making it pay?
When I cut my own, I know there are not any obstacles to puncture tires and wreck blades and gear box, etc. But in foreign territory, I have found all kinds of surprises. One was pretty costly and I had to eat that myself.
I overlap enough to pick up the tire trampled grass, as well as keep the rpm up, ground speed down, and mow low to the ground. Helps that the blades are sharp too, and not too wet (as others say) so the cut grass doesn't build up under the deck, restricting the air flow that is needed to draw the grass up into the cutting line.