1. Breath properlyThe breath is really important when stretching because it helps you relax the body allowing the muscles to stretch properly. If you take a stretch too far too quickly you will start to shake and as soon as this happens you won't benefit from the stretch. Your body starts to panic and your breath gets short. Work towards a smooth breath, long exhales through the nose, restricting the breath slightly in the throat. With the in breath continue to breath through the nose, and concentrate on the posture of the stretch - EG. When reaching the arms up while standing (image 1); on the inhale breath lift the rib cage up, draw the lower ribs back and pull the belly button in towards the spine to keep a strong posture. On the exhale breath calmly try to allow the arms to stretch further behind the head, keeping the strong posture. Interlace the fingers and reach the palms out away from the chest before you gradually start to lift with the breathing. Keep the fingers tightly interlaced, don't sacrifice the hand position to let the shoulders off the hook! Take it to the point where the fingers start to peel apart and then breath into it to see if you can keep the fingers together, posture good and work into stretching the shoulders.
2. Work towards changing things every daySometimes it's difficult to make time to stretch everyday, but you need to maintain your posture somehow. There's a few simple changes you can make to implement good posture reminders into your everyday life.
Try to get into the habit of folding the arms behind the back when waiting for something, work towards grabbing the elbows (image 2) and eventually lifting the forearms away from the back.
If your shoulders are that tight you can't fold the arms behind just place the tops of the hands on the bum and gradually work them towards each other as you start to loosen up. Make sure to change the fold of the arms and also maintain good posture, not letting the lower ribs push forwards and the back to arch over the folded arms.
Another useful thing to try is to pass a strap across the back and bring each end under the armpits. Throw the two ends of the strap over the shoulders and reach the hands round the back to grab the dangling tails (image 3). You could use a few belts joined together or buy a yoga strap for a few quid. Gradually begin to walk the hands up the strap, keeping the tops of the hands facing towards the back. One hand can be released at a time to allow you to do things at the same time but as always make sure you change sides regularly and evenly.