I work from a Cognitive Behavioral theoretical orientation. What that means is that I help people uncover what is really going on in their mind, to become aware / conscious of what happens in our brains and how it impacts our behavior.
I talk a lot about how we are constantly looking for evidence in our lives that prove to us that our negative automatic thoughts are in fact a fact. That we are justified in believing "I am not good enough", "I don't deserve to be happy", "I'm always a target", "I will always be alone". What ever the message is that drives you actually is responsible for supporting itself.
Here's an example:
If I believe I am not good enough then every relationship that I have will provide me some evidence to support that belief and I will then continue to behave as if it's true. That may mean staying in a relationship that is unhealthy, not getting into relationships at all for fear that they "always fail".
If you consciously choose a new lens to view life through and combat those automatic negative thoughts, you can then begin to behave as if this new version of truth is worth supporting. As you move into this new way of perceiving yourself, you will begin to have a new perspective of yourself, others and your future.