It's something I've mentioned on many occasions and I feel it's that important to keep bringing up the subject. Warm up! I train most days and see so many people in the gym jumping straight into their heavy lifting sets with zero warm up 😕. Innevitably leading to injuries
Each session you should begin with up to 5 mins of some source of cardio. This is to raise body temperature in anticipation of the workout
Next perform an exercise for the muscles you will be workoung with a light weight concentrations on slow eccentric contractions. This is to help the release of synovial fluids in the joints (your bodies natural lubricant) I'd especially work on the shoulders if doing upper body work
Increase weight over 2-3 more warm up sets to prepare the muscles an their accompanying joints before you hit them big numbers. This will also help reinforce good movement pattern
Stretch inbetween sets!