When you think about striking, what comes to your mind first. hmm... Punch. Punch is a common strike. Whether someone practices martial art or not, he can throw a punch. You hit with your knuckles and it can make some serious damage.
If you practice martial art, you know how to throw a punch properly. Fighters usually wear gloves in a fight. It protects your hands, and your opponent might not get hurt that bad. How about when you fight for self-defense?
You do not know when and where you have to fight to protect yourself. You can assume you will not have gloves when you fight on the street. The thing is, if you hit somewhere hard with punch, you might hurt yourself as well.
Instead of punching, you can do open hand strikes. It is highly effective in a fight for self-defense. By the way, if you do not have any training, you might not strike like that. I highly recommend learning martial art and self-defense.
Palm strike is one of the most effective strikes in a situation where you fight to defend yourself. You might think about what damage it can make, as a matter of fact, you can make serious damage by doing palm strikes.
You can also simply slap and hit with your palm. You can do it from different angles. In a fight, you are not waiting for a setup, you are fighting from where you are. You will not get a nice and clear environment to fight. You need to make your move adapting to the situation.