A personal trainer at a gym who is well in demand can make around $25 an hour.  He or she should be very physically fit and attractive.  Yes, it makes a difference if you are attractive in this business.  You should also have a great personality and be able to develop a good rapport with people.  Charm goes a long way when it comes to being a personal trainer.  You can learn to use exercise equipment properly and how to instruct someone to exercise, but learning charm is a bit more difficult.  The more charm you have, the more successful your career will be as a personal trainer.  A personal trainer who has an array of affluent clients will usually get them by word of mouth and can earn anywhere from $250 an hour on up for his or her services.