Professor What If has some advice and observations here. Below is an excerpt:
Every time a semester is about to start or has just started, my email box is inundated with”URGENT”pleas from students. Many of the things they are writing about are in fact not urgent at all. Rather, most often the information they seek could be easily found at the campus website. Another common”urgent”type of message relates to the fact they would like to add my class to their schedule AND would like to me to give them special consideration for umpteen different (almost always non-urgent) reasons. So, to those of you out there starting a new semester, before you email your Professors, please consider the following (rather cranky) suggestions:
1. For goodness sake, spell her/his name right! And, on that note, would editing for spelling/grammar kill you?
The conclusion is very trenchant too, and says in pertinent part:
Remember that such correspondence shapes your professor’s impression of you. If you come off as arrogant, demanding, self-centered, selfish, lazy, etc, many professors just might remember this about you. We are, after all, mere mortals.