Do I use quotations when writing in the first person?

Yes.

No, certainly not. Entire novels are written in the first person without quotation marks for the narrator. Any simple declarative sentence is presumed to be in the voice and opinion of the author. The exception might be if you are quoting yourself in reference to a previously uttered or published remark or if you are presenting dialog between you and others.

No, not in this case. External dialog, yes. Internal… No, don’t think so.

If your whole story is a first-person narrative, no, no quotation marks for that. Use quotation marks for actual speech of your focal character and others.

Different novelists use different devices. For actual thoughts, some use italics, but this device can get very tiresome, especially if there is a lot of it. And there may sometimes be a fine line between the character’s narration and an actual thought, since it is all, in a sense, his or her thoughts. Don’t start something that’s only going to get in your way and annoy the reader.

Some writers start a new paragraph for internal monologue. Some express actual thoughts without quotes, but set off, like this:

The rain was coming down heavier now. Too wet to go out, I thought.

If your character speaks to himself out loud (“Oh, no!” I cried.), yes, use quotation marks.

I personally don’t when writing in the first person. By definition everything is coming from the same person so it’s unnecessary. I don’t sweat those kind of details to be honest as there’s always someone to read through it.
Write it anyway and then pop it all through a spell-check and then you can blame your PC if theres punctuation errors! :0)

It depends partly on the voice you’re using. Are you (as the narrator) talking to yourself? Thinking both sides of a future or potential conversation, for example? In that case, definitely do use the quotation marks to set off “internal conversation” from “thought”. For “just thoughts”, no quotation marks are needed.

I wonder if I’m right, but I’m sure that I am. “What do you think?” I could ask.

It’s about how the sentence is structured. If the narrator is just narrating then you don’t, but if you use phrases like: “I thought” or “I said to myself” then you use quotation marks, and you always use them for spoken dialog whether it is the narrator’s dialog or not.

@CyanoticWasp Thank you, can you give me another example to make sure that I understand?

@EVERYONE ELSE:
This is very helpful. Now I am encouraged to keep writing. Not gonna take a brake. I will take another hack at the story. [Thinking to myself – thank you, Flutherites!]

p.s. Notice, no quotation marks

I think that most other respondents have already given you good descriptions of when not to use quotes. That is, for pure thought: I wonder if I can make this? (Also past tense: I wondered if I could have made that.) no quotation marks are needed.

On the other hand:
“Self, what the hell are you thinking?” I wondered. “You’ll never make that.”
“I might, and that’s why I’m going to try.”
“Well, it’s your funeral,” I thought. “Good thing it’s prepaid.”

I have also seen writers, when writing in the first person, use an offset indentation to differentiate the story line, as told by the first person narrator, and a thought process. (I have used underscores in place of tabs to indicate an increased indentation.)

“As I was walking down the street, I thought to myself,
_________I wonder if he will be at home? He said he was going to the store, but that _________was about three hours ago.

Hoping he would be home from the store by now, I decided to go to his house…”

Internal dialog is not put in quotation marks. Only spoken dialog. When I write a story in the first person, I usually put internal dialog in italics, though that’s not the norm

If you’re a beginning writer, I strongly urge you to follow conventional wisdom and write in the 3rd person in past tense until you get more experience.

what if my charactor is thinking it but i want to give the reader the impression hes talking?

Anytime you are writing in first person, there are times when the narrator is telling the listener a story (past tense) and times when the narrator is an active participant in the story being told (present tense). Sometimes, as an active participant the narrator is talking to other characters and sometimes thinking internally. As long as I am consistent, would it be effective to mark those internal thoughts by beginning them with an asterisk?

@tacotacotaco what if my charactor is thinking it but i want to give the reader the impression hes talking?

Example: I was at the train station where we had agreed to meet. I saw her as she stepped off the train. “Hey! Brenda!” I called, trying to catch her attention. “She really looks hot today,” I thought to myself.