I had a roommate once who couldn’t believe that I had never before punched someone, let alone that I had never been in a fight. His family is really into martial arts, and he has trained since a he was ten in Muay Thai and Tae Kwon Do, and he spent most of high school knocking out other amateur fighters in martial arts tournaments and backyard boxing matches. He took it upon himself to train me in the fundamentals of hand to hand combat; he taught me how to punch by having me hit the couch cushions as he held them up. Hopefully I will never need to use these techniques in a physical confrontation, but if I do the time I spent training with my roommate will pay off if I am ever in one of those situations.
Self defense is probably as much a matter of mental preparation as it is technical skill. Although some technical skill is beneficial when defending yourself from an attacker, the main challenge lies in responding to an unexpected attack with confidence. When you’re in a situation when your personal safety could be compromised, you usually arrive in that situation unexpectedly, and the assailant has the significant advantage of surprise. By training in hand to hand combat, you will have a better chance of responding confidently because you will be able to trust in the training that you have received in similar, simulated situations.
There are many options available for people who are interested in learning hand to hand combat in preparation for situations in which they would need to defend themselves. Structured martial arts, such as Muay Thai or Judo or Jiu Jitsu, give those who study it a formal and stylized approach to hand to hand combat that is centered on a particular philosophy. Selecting a martial art to study has the advantage of being centered on a certain style of fighting, so those who study martial arts can select a discipline that they feel is suited to their natural abilities and their preferences for fighting. For example, a friend of mine from high school studied Tae Kwon Do for years because he is very tall and has long legs, so the use of powerful kicks in Tae Kwon do suits him well and allows him to engage attackers from long distances. Muay Thai brings you in close to your opponent and uses quick and powerful blows to inflict massive damage in minimal time, so it would be a good match for someone who has a healthy amount of aggressive energy and is willing to unleash that on an assailant. Researching other martial arts styles can help you find a style to focus on that plays to your natural abilities.
Another sport that has become popular in recent years is MMA fighting. While most people do it as a sport it has become a popular in self defense and training. The skills these fighters can be used if you become involved in an altercation. You could take classes at a local gym that focuses on MMA or you can buy MMA exercise equipment and teach yourself.
Outside of defined martial arts styles, there are many classes taught on self defense that focus on practical techniques and real-life situations rather than focusing on a style of fighting. Most communities will have these classes available, and they are a good way to help you feel confident in yourself and able to defend yourself when it is necessary.