Everyone has beliefs learned from their experiences. Some of these get discarded as we gain more experience but often its hard to let them go if they are unproductive, unless we think about them consciously.
You may think its not too important what you believe. You are wrong. Beliefs become the rules by which we live.
Think about some of the beliefs you have. You can identify them by answering questions like 'life is....' and 'i am.....' In answering these soul searching questions you can examine how you might have limiting assumptions holding you back from being what you might want to be.
For the beliefs you would like to be rid of, imagine yourself without them and how much better you might feel....this approach has its basis in NLP or neuro linguistic programming where the brain can be trained to produce positive outcomes.
By running this simple exercise over and over, your brain will link more pleasure to the positive belief and throw our the negative ones. Providing you the incentive to move on with your life and actualise what you really strive for.