It's not hard at all to get a job at a commercial gym if you present well. I was hired on the spot and was approached by two other gyms while I was working for one. Which reminds me, compare the pay-scales of various gyms. They are not equal.
There is a lot of competition, but there's also a lot of demand. Society keep getting fatter
You could train pretty much anywhere, but I'm sure it's easier in the city.
Anywhere from 10-40 hours a week with my average being 25-30.
The days varied A LOT. Some days it was 9 people, other days 3.
My clients varied a great deal. I trained grandmas, jocks, business women, reclusive nerds, etc I did find that I really liked nearly all of them. It's a good business if you like dealing one on one with people.
Yeah, it's pretty easy to make that amount. If you're good and you stick with it, you can make 3x that. The summer is usually slow.
Those are both VERY important, IMO, if you want to maximize your success. The most sought after female trainer at my gym was a bodybuilder who had her abs posted all over the place. I didn't see her make a lot of progress with most of her clients, but that didn't matter as much as the fact that she'd made progress with herself, in terms of her monetary success. The top selling people in the company where a 10 in terms of looks. Only one of them was really worth how much he was being paid.
Another thing- there tends to be a trainer hierarchy at gyms. There's one trainer who usually is considered the veteran and everyone is hoping to train with him. If you can get trained by him, it will boost your position in the gym, even if he's not the best trainer. I would recommend becoming that guy's right-hand man.
I did functional movement testing on my second meeting with my clients and spent the first getting to know them and showing them what they didn't know. I didn't train anyone the same and I also didn't find that completely wearing them out every session resulted in the most sales. You have to find the balance of exertion and put people at about an 8 on a scale of 1-10 so they feel that they both feel that they are capable and that they really accomplished something that day.