Yes, there are. Try to go through the following few successful routines to get the posture into its most natural and needed position:
1.Stand with your back against a wall. Your heels should be 3 inches (say 7 cms.) from the wall. Now imagine that the top of your head is attached to a rope which is knotted at the ceiling end, and that you are being stretched up to the ceiling. Now press both shoulders back against the wall, and slide your head back so it is touching the wall. Keep your eyes and chin level to the floor. Keep your abdominal muscles tucked firm – don’t let them hang loosely forward.
Once you are able to get into a comfortable position – not always so easy at the start - go to the next step which is to slowly bring your head as far forward as possible without letting your shoulder blades come away from the wall. It sounds like you have to be a contortionist, but you don’t. Keep your eyes and chin level to the floor as you now slowly slide your head back again to try to touch the wall. Repeat this five times and finish with your head in the back position.
Once you have your head back as far as possible try to maintain that head alignment while you step away from the wall. This position is where you want to try to hold your head when you're standing or sitting. If you ever notice your head has slipped forward into your old faulty posture, just practice these movements a few times and again try to keep the head, neck and shoulders in a proper alignment.
2.The next movement is designed to help you determine where your pelvis should be, and it will also help develop flexibility for your lumbar spine and increase your range of motion. Stand some 3 inches (say 7 cms.) from the wall with your feet about one and a half feet apart. Bend your knees slightly. Bring your lower back into as much of a curve or “sway back” as possible without creating pain, that is to move the buttocks backwards towards the wall. Don't squeeze your buttocks to do this - it should all come from concentrating on tensing the abdominal muscles.
Repeat this movement five times in slow deliberate repetitions. Don’t move the upper body (torso). The pelvis should be the only part that is active.
You will need to push yourself to do these movements on a daily basis. So be regular and work on these corrections throughout the day, every day.
At first these corrective movements won't feel natural, and they will feel forced and awkward. That is because 'forcing' the good posture in to its correct position is exactly what is happening. But eventually it will all fall into place. You will soon be able to make corrections as a matter of habit. You will automatically try to maintain the correct posture whilst going about your daily activities.
The more time you spend in the corrected posture the easier it will become because your tight muscles will be stretching, your weak muscles will be strengthening, and your brain will consistently be reminded of where you 'should' be. Eventually it will become natural to hold yourself in a proper posture without your awareness or conscious control.