How to properly warmup
Cardio
A lot of the time you will see people walk right into the gym and walk straight to the weights and start lifting cold. Spending 10m on a piece of cardio equipment allows for your blood to start circulating faster, your body start to warm up, and allows for you to mentally prepare for the workout at hand. This would be a time to review your workout then put down your phone and focus on what your about to accomplish this session.
Abs
So i got this idea from Kia Greene years ago and since have kept it in my routine with the exception of some experimental phases in training. Our core is activated in every exercise we do to keep us stable, some exercises more than others from a squat to a bicep curl. So doing a 5-10m ab routine in the beginning of each workout is a great benefit, especially for the big sessions like pulling or legs where our core is highly involved. The routine i like to do is all floor work. Fifteen reps of each exercise(start with 5-10 and progress) starting with a modified crunch, elbow to knee cross crunch (each side), side lying oblique crunch (each side) and lying leg raises. All reps performed with the utmost control focusing on actually feeling the area your trying to target rather than just getting the movement done.
Bands
In almost every exercise we do we are putting our rotator cuff through some type of circumduction. To allow for minimum discomfort/chance of injury and maximum efficiency warm-up with resistance bands. Keeping constant tension and bringing the rotator cuff through a full range of motion with bands allows for the tendons, ligaments, joints and muscles to warm-up instead of just going straight into a exercise cold. Two exercises i like to perform when warming up with bands are “around the worlds” and “band pull aparts.”