Meditation is more about being alert, observing the mind, than just sitting in a certain position. The only goal it has is to still the mind so that our true self, God, can come through. We should be in control of our mind, not the other way around.
Tensions in the mind are stored in your body. Any form of relaxation practice releases this tension and it will become easier to keep the mind clear. Relaxation itself can become one form of meditation if concentration is achieved.
It is good to keep yourself clean because impurities on the body become easily impurities of the mind. Breathing is strongly connected to our mind. Learn to breathe deep and long inhales and you will stay more relaxed.
Affirmations can be used for concentration. They help to push away any other thoughts that try to come into your mind. When proper concentration is achieved, mind will get still by itself and nothing will be left but silence. Total peace!
The goal is to keep up a mediatative state whenever possible. Chanting in your mind regardless of what you are doing will help you still the mind. It is good to choose affirmations with care because those vibrations will become a part of you.
You can also do visualizing meditations. Still it is good for us if we have at least few minutes every day when our mind is in total silence.