Sometimes, this entails only having a short visit, in which the therapist uses crisis counseling. Sometimes, however, people go into a therapist's office with a crisis and find that there are things that underly it that you want to uncover or work on. At this point it is no longer intervention, but on the path to psychotherapy. Another time that is common for people to go a therapist is for specific non-crisis problems, such as insomnia, procrastination, low grades, or even feeling depressed. The defining factors is that the person does not have an immediate threat to life but has a specific identified problem to be worked on.
Many people tend to go to cognitive-behavioral therapists or rational emotive therapists.
I had a psychology professor who argued that specific behavioral or emotional problems are best treated by the cognitive behavioral camp, so you might keep this in mind if you chose to go into see a therapist, however I am a little less adamant about this distinction. An example of this is a person who comes into to a therapist's office because they are having trouble in school. This might be the result of many factors, such as interpersonal problems, an addiction or alcoholism, an eating disorder, etc. This might also lead you to psychotherapy. Finally, what used to be the most common type of therapy, and now is a dying art, is personal psychotherapy.