WARM UP
Remember to warmup at least for 5-10 min before working out! Warming up is as important as drinking water every day. Warming up should gently prepare the body for the exercises you are going to do by gradually increasing the heart rate and circulation; this will loosen the joints and increase blood flow to the muscles. Stretching the muscles prepares them for physical activity and prevents injuries.
You can warm up in different ways, depending where you will do the workout. I always start with some kind of cardio exercise, for example:
Skipping ropes 5-10 minutes
Jumping Jacks 50-100 (plus other things i.e. mountain climbers, burpees etc)
Jogging 7-15 minutes
If you have your own routine, do that.