Lets start with work. This is an activity most people fill their days with. working 9-5 and maybe working out after. Rinse, repeat. Work is something to be endured, the daily grind, it is rarely engaging, often mind numbing. All worth it for payday. Described like this it doesn't sound conducive to a successful mindset.
Practice, by contrast, is a purposeful activity. When you step on the field you have a clear aim in mind (assuming a knowledgeable coach), there are goals with metrics to measure your achievement against. Practice drills are designed to take aspects of performance and improve them. You are engaged, present in the moment, listening to feedback, making adjustments and taking those baby steps towards a complete performance. You simulate game conditions and test your skills against them. Performance and improvement are always at the front of your mind. When you leave the practice field you do so satisfied with your improvement, developing ideas as to how you'll develop things further next session.
Hopefully you can see where I'm going with this. Why should practice be reserved for the athletes whilst the workers grind onwards? Why can't we take the ideas from 'practice' and apply it to 'work'?
So how would this look in reality? Lets start with the first principle of practice mentioned above - clearly defining the aims of that session. So when you go into work tomorrow, rather than idly checking email with your fingers crossed for no pressing disasters that'll delay your Daily Mail perusal, set yourself some goals. What do you need to achieve? What do you want to achieve? List them and break down what needs to happen for these aims to be achieved. Then set yourself a time limit and get going. You can then think about how to measure your performance. Is your work based on quantity or quality? What existing metrics are available? What targets can you set yourself? How can you improve your performance to hit and surpass these targets?
Start asking yourself the questions above. Transform your office into the practice field. Keep performance at the front of your mind and keep challenging yourself to improve.
Then when you leave work for the gym, throw out your old workout. Rather than half heartedly following a body part split regime from an old Men's Health start thinking like an athlete again. What performance goals can you think of? Whether it's your first pull up or a 200kg squat, define it and create a program to achieve it. Rather than absent mindedly pushing out sets of DB Bench engage with each exercise. Can you improve your form? Can you push the weight? This is practice time, stay focused on improvement. That is when the results start to appear.
As the saying goes 'if you aren't moving forwards you're going backwards'. If you have career ambitions quit thinking like a worker, embrace an athlete's mentality. The office is your field, the clock is ticking and you've got the ball in your hand. How are you going to use this time?