If it says nothing, delete it!

Don't leave something in your paper just because you wrote it. You may feel protective toward the words you have created. Don't - the best writers are ruthless about editing themselves. If a word or sentence is not doing anything to make your paper better, kill it.

As the great American writer Mark Twain said: "Writing is easy. All you have to do is cross out the wrong words."

What is 'it'? Ambiguous reference of pronouns

What is wrong with the following passage?

The boy threw a glass at the man's window, and he broke it. He was very mad at him.

Well, for a start - who broke what? Who was mad at whom? Maybe the man was lucky, and his window did not break, but he was so angry at the boy that he broke the boy's glass. It's impossible to tell for sure from the passage above. A pronoun like 'he' is said to refer to the word it stands for, and it is your job as a writer to make sure that it is easy for your readers to tell which word a pronoun refers to.

Use vs. mention - some uses for quote-marks

When you are talking about a thing, you use a word to refer to the thing. When you want to talk about the word itself, this is called mentioning the word. When you mention a word or phrase, you should indicate that that is what you are doing by putting quotation marks around what you are mentioning.

For example: A duck is a kind of bird, but 'duck' is a four-letter word.

Word order changes your meaning

Unlike some languages, where the form of words makes it clear what grammatical role a word plays in a sentence, English grammar is based partially on the positions of words in relation to each other. Pay careful attention to the way you arrange words into sentences, or you might accidentally say something very different from what you meant to say.

For example: "It is not true that I do not care." Means that you do care about whatever you are talking about. But: "I do not care that it is not true." Means that, whatever you are talking about, you don't care if it's a lie. This is very different!

Active and passive voices

A sentence like "The dog howled at the moon." is written in the active voice, because the subject of the sentence (the dog) is also the one who is acting. On the other hand, a sentence like "The moon was howled at by the dog." is in the passive voice, because the subject of the sentence (the moon) is being acted on (by the dog). It is generally considered better style to use the active voice, when you have a choice.

Parallel construction

When you have several clauses, all part of the same sentence, and all sharing something in common, or when you have several sentences together which are supposed to express related ideas, you should try to make sure that they are similar in structure. This means that if they all start with verbs, the verbs should all be in the same tense, and in general they should resemble each other grammatically.

For example:

Bad: The delegation included Panamanians, Pakistanis, and also people from Canada.
Good: The delegation included Panamanians, Pakistanis, and Canadians.