I'm so dang excited to step back into the gym but if you're like me and you've barely touched any heavy weights or equipment in the last few months, please don't get TOO excited and wreck yourself with a workout that your body isn't used to anymore. You might just miss a few more weeks at the gym because of it...
Don't see your next workout at the gym as a way to make up for lost time. Your body has most likely been deconditioned from the amount of volume and intensity you were doing before gyms shut down.
Remember your 'why' behind your training. I'm sure it isn't to fry your nervous system or make yourself so sore that you can't go to the gym for another week.
If your 'why' is a specific performance goal you were working on before gyms closed down, don't get demotivated if you are no longer at the progression or weight you were at before. Instead, be patient with yourself and use yourself as motivation. If you've done it before, you can do it again. Use your first few weeks back to get reacquainted with your body and prioritise on technique before you focus on increasing volume and intensity.
If you had trouble making time for the gym before and your 'why' is consistency, focus on behaviour and habit. Make 'going to the gym' something to tick off and see it as a win every time you go. Not every workout may feel great afterwards - I remember when I first started going to the gym I would walk out feeling negative because I would think about all the things I couldn't do or think about how long it would take me to reach a goal. If you're trying to make 'going to the gym' a habit, make yourself feel successful every time by celebrating your following through with the commitment you made. Associating the gym with feelings of success right at the start of your journey to consistency will make it more likely that you'll keep going back and make going to the gym a habit.
If your 'why' centres around aesthetics, don't forget that exercise is only one part of body recomposition. Don't get upset if you aren't able to frequently get into the gym. Focus instead on the other factors of body recomposition that you can control, such as your nutrition, hydration, steps (non-exercise activity plays a huge role in fat loss!) and sleep.
You might take all of this on board, hit the gym and see other people immediately lifting heavy or doing crazy HIIT workouts. You might get a bit of FOMO and get tempted to throw out your initial plan to ease yourself back into training. Try not to compare your training to someone else's. You don't know how they have been training while gyms have been shut, maybe they are one of the lucky few who had access to heavy weights and equipment. Remember your 'why', trust your program and be patient.