How to write stuttering characters.

Okay, this is serious. I know it sounds dumb, but a lot of people really need to take this into consideration.

First off. Stuttering is not always a show of shyness or embarrassment. Often, it's a show of fear, or confusion. Characters that constantly stutter have likely been through trauma. They're not just shy. And stop using constant stuttering for your love interest character whenever they're around their crush.

Let me explain. There are two main types of stuttering, jagged and flowing. The jagged kind is mainly used to show surprise, and it's on the beginning of a word, usually only one or two words in the sentence. It's used when the character feels a sudden emotion.

The other kind is flowing. Like water. Imagine the words blurring together, repeating, merging in on themselves. This is to show confusion, or hesitance. Let me give an example.

"I...I..I'm sorry! Please..I didn't..didn't mean it. Don't go! Don't leave me..."

Compared to:

"I-I-I'm sorry! Please, I d-didn't mean it! Don't-don't go! Don't leave me-"

The first option is a little easier on the eyes, and with the context of the sentence, works a little better. Makes it smoother. Another thing to remember? The jagged stuttering looks better when it's not on a one/two-letter word, unless the word is the start of the sentence. Now, you can alternate depending on the emotion you want to give off. The first sentence is fear, and hesitance. The character is worried, and desperate, though they don't fully want to show it, which is why they hesitate. In the second sentence, it's implied the character is almost surprised, and scared, stuttering to the extreme. This also shows shyness, meaning the character is probably someone more emotional, more unused to fear. And scared of being left behind. They're blurting out all their words at once, in hope of stopping the event happening.

But it's more realistic if they hesitate at first, and parts of the sentence are rushed while other bits are flowy and doubling back on themselves. You can use adjectives about their speech to fill in the blanks.
The aesthetic choice is surprisingly important, as it can make you seem more professional. Of course, the use of stuttering depends on your character's personality, and speech patterns.
So, keep in mind that stuttering should be used sparingly. And the most important thing to remember about it, is this. Stuttering isn't a way of showing embarrassment. It's nervousness, someone who's unsure of themselves, or scared to speak. It's flowing, blurred together. 

Note: This will be updated to add more detail, and increase the length of the explanation later on. 445 words.