Okay, let's start small. Creating a character (unless you're writing fanfiction) is very important and at times, very hard.
I personally have problems with characters, too. It's very difficult to try and replicate a realistic person. Here are some tips!

Base your character on someone. This is not a must-do! I simply find it easier to borrow personality traits from people I know, as it makes it easier to decide how they would act and what they would say.

Give your character a key trait. When it comes to personalities, there's always one or two aspects that people notice the most. For instance, you probably know someone who is kind and funny. This person has much more to their personality than that, but it's what you know them by. Choosing to focus on one or two traits makes writing a character less complicated.

Backstory is important. And not just to the plot! Backstory will help you shape, define and decide certain things about your character's personality. No, you do not need to clearly know their backstory. Just a principle or idea is enough to work with! You can unravel their backstory while developing their personality throughout your story, if you want!

Nobody is perfect. Although it may be tempting to make your character flawless in every way, you should not do this. This sounds obvious, but you'd be surprised at how often you can unconsciously do this. If you're worried, ask yourself, "What flaws does my character have?" You should be able to name at least two. If not, add some in.

Nobody gets anything first try. I've read too many books (and watched too many movies) where the main character has to do something difficult and magically accomplishes it through the power of hope and love. NO. Especially when it comes to dueling an enemy. If your character has not trained, they will lose. Because their opponent is better. Because they are human. Leave room for learning and improvement! Natural talent doesn't exist!

Everybody has emotions. You can have tough characters and cold characters. But remember! There will always be a moment where even they surprise themselves with their own feelings. Ensure your character is not easily brushing everything off!

Okay, I think that's it! See you next time!