Mindfulness tools are scientifically proven to calm down your mind and slow down habitual thinking patterns, those that often lead to insecure, negative thoughts or contribute to low self-esteem. Here's a list of mindfulness techniques.
Buddhist Prayer of Forgiveness - If I have harmed anyone in any way, I ask their forgiveness. If anyone has harmed me in any way, I forgive them. And if I am not ready to forgive, I forgive myself for that.
Health is the greatest gift, contentment is the greatest wealth, a trusted friend is the best relative, Liberated mind is the greatest bliss. - the Buddha, ascetic and sage on whose teachings Buddhism was founded
Prayer is when you talk to God. Meditation is when God talks to you. However, both can go together - as you sift away distractions while Praying and get to the stage of Concentration to what you are Praying about Meditation sets in.