Character creation is a very involved and varied process.Each writer has their preferred methods, and each story has its own requirements.
Sometimes stories begin with the idea for a character and the writer has to work to create the right plot for them, other times an idea for a plot will present itself and the writer will have to populate it with the right characters.
But how do you make your readers care?
First, you have to care about your characters.
There is no point writing a story about a character you aren’t interested in. For starters, why would you want to? No matter how disciplined you are, if you don’t care what happens to your protagonist, you simply aren’t going to finish writing the story. If there even is one.
But, more importantly, your reader will notice that you don’t care and they’ll stop reading. Readers are annoyingly observant. They’ll notice the scene you found boring to write, because it will be boring to read. They’ll spot the setting you didn’t bother to think about, because your descriptions will be vague or absent. And they’ll know which of your characters you care about and which you don’t. And they will lose faith in you as a writer.
After all, if you don’t care about your characters, why should they?