Self imposed limits
Realize that your upbringing is only to blame for the systems and beliefs you have in place, not the ones you can acquire.
Trauma is responsible for faulty belief systems, not for the incapacitation of an individuals capacity to decide its next action.
One cant directly manipulate beliefs, but you can act repeatedly and start building new beliefs based on experiences you place yourself into. Discard negative experiences or learn from them when it is wise to.