There are two types of stretches you should focus on when training, the first is static which you hold for a certain amount of time. The second is dynamic which has been scientifically proven to be more effective pre workout.
Motion is lotion. Movement will lubricate the joints and prep them for the session ahead.
Here are some dynamic stretches for you to try at the beginning of your next workout.
You can do these same stretches at the end of your session as a cool down to help your mobility and flexibility or on your rest days. The only difference being rather than completing reps of these exercises you will hold each of the stretches for 15-30 seconds.