The beauty of first person is that it’s immediate. It’s like constantly being in the person’s head, constantly hearing their direct thoughts.
In third person POV, direct thoughts are indicated by italics. For example:
This is from Only Uni. My heroine, Trish, has just showed up for a New Year’s party.
Here’s the original with lots of italics.
She glanced down at her dress. Well, at least the cut makes me look curvier and slender at the same time. Ha! I love how well-tailored clothes ensure I don’t have to work as hard to look good.
She kicked off her sandals—Oh look, my toes have turned blue from the cold—and they promptly disappeared in the sea of shoes filling the foyer. She swatted away a flimsy paper dragon drooping from the doorframe and smoothed down her skirt. She snatched her hand back and wrung her fingers behind her.
Here’s the revised version:
At least the expert cut of her dress made her rather average figure curvier and more slender at the same time. Trish loved how well-tailored clothes ensured she didn’t have to work as hard to look good.
She kicked off her sandals—Oh look, her toes had turned blue from the cold—and they promptly disappeared in the sea of shoes filling the foyer. She swatted away a flimsy paper dragon drooping from the doorframe and smoothed down her skirt. She snatched her hand back and wrung her fingers behind her.
No, that’ll make your hips look huge.
She clenched her hands in front.
Sure, show all the relatives that you’re nervous.
She clasped them loosely at her waist and tried to adopt a regal expression.
“Trish, you okay? You look constipated.” Her cousin Bobby snickered.
The first two paragraphs in the revised version are essentially direct thought, but in third person past tense rather than in first person present tense and italics.
I used italics for when the thoughts go deeper, and Trish is thinking to directly to herself.
A rule of thumb in novels is to use italics as little as possible. If you use italics very lightly, then when you do use them, the italics have more impact, such as in the example above. The italics serve to impact the humorous punchline at the end of the example.
In order to use italics lightly, I tend to only use them when the character is speaking to him/herself. Other types of direct thought can easily be written as third person past tense, as shown above.
In first person, the principle is the same. Use italics lightly, and only use them for emotional impact and when the character is speaking directly to him/herself.
Here’s an example from my current WIP, a young adult chick lit. It’s Amelia’s first day at a new school and she’s just met Glory, who seems nice, but Amelia can’t explain why she doesn’t warm to her:
Glory glances at my backpack. “Nice bag.”
“Thanks.” It’s leather and heavier than a suitcase. I also think it’s kind of old-person-ish, but Mom got it for me.
“What do you parents do?”
“They’re both engineers. How about y—”
“Where do they work?”
I blink at the question. Well, this is Marshall’s School for Excellence—maybe the smart kids are more career oriented than normal folk. “Mom’s at Google, Dad’s at Intel.”
Glory’s eyes widen so much, her (fake, I think) eyelashes brush the bottom edge of her bangs. “Wow.”
Her reaction causes that same zapping thing with my back, and I take a deep breath to make the muscles loosen. Stupid, what are you doing? She’s a nice person.
Most of the chapter is void of italics. The only time I used them is here, when Amelia scolds herself for being unreasonable.
Look at your own manuscript. How often do you use italics? Can you rewrite them into the narrative as non-italics?