Train for your objective
If you don't know exactly what your goal is, it's difficult to plan for it, and even harder to measure your success. Training for fat loss is different to training to build muscle, and different again to training for sports performance. Know what it is you want to achieve, rather than just going to the gym to tick the box.
Remember recovery is as important as training
It can be as simple as listening to your body and adopting a common-sense approach to your training. Ideally, we want to balance our 'yang' (or high-intensity) workouts with 'yin' (or restorative) practices.
Go hard on your hard days, go easy on your recovery days, and avoid the 'junk miles' in between. This will not only help prevent injury, but will also ensure you perform at your best when required.
I liken the body to a bank balance: every training session is a withdrawal; every recovery session – be it foam rolling, a massage or an infra-red sauna – is a deposit.
If you're always training and never recovering, you're going to end up overdrawn and injured.
Be accountable to someone or something other than yourself
Keep a lifestyle diary to help you to identify potential limiting factors outside of the gym; track your food in MyFitnessPal to bring awareness to what you're putting in your mouth; hire a personal trainer who'll charge you if you cancel a session; or join an online programme with a social media community who'll encourage you to share your journey while supporting others.
Understand the difference between motivation and discipline
You won't always be motivated to train, but you don't need to be. Motivation doesn't get you results, discipline does. Day in, day out, you just need to turn up and get the work done.
If motivation is an issue for you, try taking before and after photos (visual progress is a powerful intrinsic motivator), finding a good pre-workout tool to pump you up (a shot of espresso is simple and effective), downloading a new playlist, and/or visualising how good you'll feel after you finish.
Prep your body for movement and make your training more efficient and effective
A solid dynamic warm-up primes the nervous system, addresses any structural imbalances, identifies potential weaknesses in your body and reinforces correct movement patterns. I always start my training sessions with hip mobility drills followed by specific glute-activation exercises.