Therapy starts with the initial consultation. Very often just having the chance to talk to someone on total confidentiality about your problem can help. Analyzing why the problem exists and how it started can be a benefit.
When we have a problem we become stressed, anxious and worried. Hypnotherapy can help us to become more relaxed and you can learn to to relax yourself.
Some times it is the belief in a problem and thinking constantly about it that can perpetuate it. The negative feeling the problem gives us grows and we then feel we can't change and will never be able to resolve it.
Positive suggestions during hypnosis can make us feel more positive that we can overcome anything. Belief in our self can change our feelings about the problem and ourselves.
The above are general ways that therapy can help. They will relieve most psychological and emotional problems. Therapy can help in many other ways but it depends on the specific problem.