To Break the Rules or Not Break the Rules; or is it Optional?

The Assignment: What were you taught NEVER to do as a writer? Come up with about two or three such mandates, and write some of your reflections about each one. Was this rule a good one? Are there sound reasons for it? Are there times when you can/should ignore it?

So the above sounds fairly easy, until I went to start writing and my mind drew a blank. The first thing that entered my mind was the use of the comma (,) and the semi-colon (;). I personally have a love/hate relationship with these two pesky tools. I know they are important in writing, letting the reader know when a pause is coming or a list. My problem is I can never remember when I absolutely must have them or the proper use of the colon and semi-colon. I tend to lean heavily on the use of a comma, figuring when I spell check the item being written, spell check will graciously throw the proper one in where it is needed. Not the best philosophy I suppose, but it manges to save me - most of the time.

Another rule of writing that tends to confuse me is making the subject and verb agree with each other, not with a word that comes between them. I have to really stop and think this through, because I tend to think that the proper way sounds "funny", not funny ha ha, but funny as in not correct.
For example, I pulled the following example from a website about the Rules of Writing, see foot note.

"Incorrect: The girl, along with her classmates, like the new teacher.

  Correct:   The girl, along with her classmates, likes the new teacher." (FN1)

To me, the first one sounds perfectly fine and I would not have hesitated to write it as such. While I can understand the rule, it is not one that I would promptly find if proofreading a paper. I also think that this is one rule that is consistently broken when writing papers.

The third rule on my list is the use of unnecessary words. While I "get" the fact that when writing, people tend to add in tons of useless words as filler. I think a lot of it is due to the fact that papers have to be so many pages or so many words. While there is ways to go about not using these unnecessary words and presenting a concise, well thought out paper, many are so used to using them it becomes a natural tendency, not only in writing but in speaking as well.

Foot Note 1: http://junketstudies.com/joomla/11-rules-of-writing/the-rules/79-rules-of-writing/90-rule07