For a mild problem you would be doing between 8 to 14 sessions of about an hour each.
The aim would be to indentify a problem. Then identify the "hot thought", the emotion it creates, how strongly you feel that emotion, and then the evidence you have for it.
You don't push that thought away, the therapist doesn't try to correct it. You sit with it for a few moments. You learn to identify the physical changes your body goes through (increased heart rate, sweaty palms, faster breathing, tense neck etc). Then you think of different evidence. You think about that new evidence, and say if it affects how strongly you feel the original hot thought.
It's an iterative process! This is just a very quick description - it's a bit more involved than that.
You're right - movies are terrible portrayals of mental health treatment. Like CSI does computers level of bad.
And it still had a lot wrong with it.
Most importantly, they are detached from the situation (unlike a coworker or friend) and have professional training and experience at helping people with their problems.
Often times when I see a psychologist I end up figuring out how to improve my situation on my own. Having a place to spend time thinking about the issues in a calmer way, and the occasional suggestion or a good question, let me tackle my issues from a different point of view. Repeated visits (once every two weeks to start, then once a month) for a period of time provide motivation to put these realizations into action. When I feel better, I stop going.
I've often mused with the idea, perhaps there is some systemic issue that I need to have help with identifying and resolving... But then...what? Perhaps we have all seen way too many movies involving psychologists/psychiatrists, that it's slanted our view. I know it has slanted it for me.