I would say to work smart, not all the time!
Have a niche, stay current, be versatile, contemplate flexibility, anticipate change, stay educated and on top of your game, love what you do, follow your strengths.
Sometimes making a long term plan can be a hindrance, as one never knows what lies ahead.
The answers are all fantastic. Be who you are and what you are. Susan’s suggestion to anticipate change is right on the mark. We all deal with a wide variety of people every day. From the quirky matron to the steadfast male of the kingdom just be flexible in all of your answers to all of their questions. On top of it all, as Susan suggests, stay educated. There is so much information, and it evolves everyday. I know that you will have a great career.
The best advice I can give is to seek a path to specialize in. It might seem counter intuitive to narrow your scope to a specific realm of fitness but you’ll increase the amount of business that will come to you. With basic certifications you are able to guide a wide range of people through workouts, however so can everyone else with a basic certification. You need to find away out from the crowd so you can stand out and offer something that fewer trainers can. Once you are more specialized you will find that more people will seek you out rather than the other way around. Think of it this way, if you are a trainer that specializes in marathon prep/training you are narrowing yourself toward that field. However, if you were someone wanting to train for a marathon would you seek a run of the mill trainer or someone who specializes in what you are training for? Obviously people will want to find someone that can meet their specific needs. So in the long run although you are narrowing your scope you will find more clients willing to seek you out and pay more for that specialization they cannot get with any other trainer. Just find out what interests you the most or where you have the most experience and capitalize on that.