It is rare to find someone who, at some point in their life, has not questioned themselves. I'm not a good enough student. I'm not good enough at my job. I'm not a good enough partner. I'm not interesting enough. I'm not attractive enough. To some degree, it can be normal to experience self-doubt, however when these doubts are persistent, hard to shake, feel real, is when they can really begin to effect your life. Many suffer from "imposter syndrome", the feeling that, if others only really knew me, they'd see what a phoney I am. They'd see how incapable I am. Dan understands this experience and can help you find a balanced way of seeing yourself. You are not perfect, and that is perfectly OK. You will mess up. You will make mistakes. Therapy is not about ignoring these facts, but helping you to embrace these imperfections, while noticing your gifts as well.
Depending on where you are at, you may benefit from CBT or IFS in increasing your self-esteem. Dan typically works more with IFS strategies to help you increase your compassion towards the parts of your self that feeling inadequate. Offering this compassion can help these parts truly internalise that they are good enough. You may not believe it, but Dan believes that all of your parts are enough. Sometimes they've just needed to act in extreme ways, because its the only thing they know.