Since you will not use contractions, you should use apostrophes only to show possession. It's always means it is . Never use it's in formal writing . Avoid starting sentences with numbers. Avoid redundancy .
Redundancy comes in two basic forms.
The first is using the same word over and over. The second form of redundancy is unnecessarily repeating an idea. If you say Marx wanted to abolish private ownership of property, do not repeat the idea several times in your paper. Instead, proceed to explain why he wanted to abolish private property, or how his idea was implemented. A void slang and colloquialisms in formal writing .