I would like to highlight the following interesting material as an example. It is necessary to mention that writing regulations will depend on the area you are writing for.

Common Writing Mistakes to Avoid

1. Avoid the 1st person (I, me, my, we, us, our) in formal writing.
2. Avoid the 2nd person (you, your, yours, yourself) in formal writing.
3. Avoid contractions in formal writing. Instead of writing don’t, write do not, etc.
4. Periods and commas go INSIDE quotation marks, not outside.
5. Use the active voice instead of the passive voice:
   1. Passive voice sentence: The paper was written by him.
   2. Active voice sentence: He wrote the paper.
6. Be consistent in your verb tense when writing papers; do not switch back and forth between the present and past tense.
7. It’s = it is (a contraction); its = possessive – something belonging to it.
   1. It’s really hot outside. (It is really hot outside).
   2. Every class has its own personality. (This is possessive, even though there is no apostrophe).
8. Use semi-colons correctly. There are only two ways to use semi-colons correctly:
   1. Connects two COMPLETE sentences that are very closely related. Ex: The right to vote in local and national elections is something that many people in the world do not have; for this reason, many people believe that anyone who is eligible to vote has a responsibility to do so.
   2. Used to divide items in a series when a comma is already part of a clause that makes up one of the items in the series: Ex: There are basically two ways to write: with a pen or pencil, which is inexpensive and easily accessible; or by computer and printer, which is more expensive but quick and neat.

(From: http://writing.wisc.edu/Handbook/Semicolons.html)