Using the right tone

You’re so wrong.

I can see your point, but I disagree because . . .

That chick doesn’t know what she’s talking about. It’s stupid to think that war is like a disease.

I disagree with Savannah’s view that war is like a disease. Although I understand her argument, I feel that she could have used more convincing support.

Offering sound advice

Awkward.

I’m not sure what you’re trying to say here. You might want to clarify this sentence by . . .

I don’t understand this paper at all. You don’t make any sense.

I was confused by the main points in your paper. You might want to reread the assignment or ask the instructor for help.

Eliminating confusing slang, idioms, and jargon

Sup?

What’s up? How are you doing?

You shouldn’t look a gift horse in the mouth.

If someone offers you helpful advice, you should be grateful, not critical or defensive.

IMHO, you need to back this up more.

Can you provide more evidence to support your point?