Be suspicious of any attachment to an email. Text can't give you a virus but attachments can. Learn the filename conventions used.
Filenames come in the form name.extention.
If you receive an attachment with the name mymovie.mpg you know by the extention mpg that it is a mpeg movie named mymovie. Know the safe and unsafe extentions. Be extremely careful of any other ones. Also, be aware that windows doesn't always report the correct extention. If the attachment name is goodpic.jpg.scr windows will often report only goodpic.jpg which looks ok but in fact the extention is .scr which could very well be a virus.