One problem I'll mention is ambiguous pronouns. If you *really* think about it, you can usually figure out what the author is referring to. Here's an example that was topical like a month ago:
"President Obama told Vice President Biden that he supported same-sex marriage."
This isn't the most ambiguous of examples, but the "he" in question could be referring to either the President or to the Vice President. I've seen much worse examples. Anyway, here are some links to websites with advice on avoiding this issue:
- SparkNotes: Ambiguous and Vague Pronouns (mostly SAT advice but generally applicable)
- Pen and Page: Pronoun Reference (extensive, with lots of examples in different categories)
- Methodist University: Vague or Ambiguous Pronoun Reference (includes links to some exercises)
It might be tedious, but if you think you have trouble with pronouns (or if someone has told you that you do), do a "find" operation in your word processor and look for all "he," "his," "them," "she," "her," etc. Then see if you can draw a line back to the original reference for each pronoun. If you can't, or if there are multiple options, please reword the sentence.