When you proofread look for punctuation, spelling and Capitalization Mistakes.

is this punctuated correctly?

No. It needs another comma. Also there are capitalization errors.

I need help with this!

To determine if the sentence "When you proofread look for punctuation, spelling, and capitalization mistakes." is punctuated correctly, we need to check if it follows the standard rules of punctuation.

First, we should make sure that there is correct use of commas. Commas are used to separate items in a list, and in this case, we see that the sentence correctly uses commas to separate "punctuation," "spelling," and "capitalization mistakes."

Next, let's check the capitalization. The sentence starts with a capital letter, which is correct. Additionally, the words "Punctuation," "Spelling," and "Capitalization" are capitalized since they refer to specific categories.

Based on these observations, it appears that the sentence "When you proofread look for punctuation, spelling, and capitalization mistakes." is properly punctuated.