Spell check your work. This is a major source of aggravation. Such individuals will assume, every time, that a typo is bad spelling and you will get flamed for it. So where you come from the hunt and peck school of typing watch for this. While this is annoying they aren't out of line expecting good readable material.
Communication is the point here.
If spelling inhibits your communication channel to your reader then handle it. Such little fixups are always wise to do before uploading otherwise you will find yourself correcting and uploading corrections over and over. The main file on your site should be named index.htm . Similarly file extensions are important to take note of. Dos simply wont read such a file format and sits there looking like the idiot it is.