Cleanse the mirror of your heart, and you will see God.
Every line of the Hanuman Chalisa is a Mahamantra.
Clear the mind of all worldly things. If you can't control your mind, how will you realize God?
If you want to see God, kill desires. Desires are in the mind. When you have a desire for something, don't act on it and it will go away. If you desire to drink this cup of tea, don't, and the desire for it will go away.
Keep God in your heart like you keep money in the bank.
Never put anyone out of your heart.