R.I'm just wondering about expression of thoughts in writing. I've been looking online and so far I've learned that italics may be used in place of quotation marks but I've also heard that either can become tiresome over the course of a 300 page+ novel. I'd like a few opinions on what is generally preferred.
Have you considered actually looking in novels to see what is used?
If you did, you'd probably find that thoughts are not given special punctuation in modern novels.
Bolt pretended not to see Melanie. He flexed his sleek masculine torso as he lay his towel on the sand. Hm, built well too, she mused. But what was she thinking?! This was the man who was so rude to her last night!
In 3rd person narratives from one character's viewpoint like this, and in 1st person writing, most of what happens is in the protagonist's thoughts.
If you read 3rd person omniscient novels with no particular character focus, you might find thoughts quoted - esp. Victorian and early C20 novels.
I also have a second part to this topic and that is paragraph structure of these thoughts. Should a new paragraph be started like in the case of dialogue or should thoughts flow in the paragraph naturally. It's really bothering me.
It depends on point of view, character focus, etc. It also depends on the writers style.
I really think you should open a few novels.