[acropolis]

As has been pointed out, the vast majority of poor spellers are, in fact, slow of the brain,

as has also been pointed out, activities which intelligent people tend to enjoy lead toward better spelling,

further previously pointed out, if you choose to use a written medium to communicate, use of proper spelling and appropriate grammar is simply common courtesy,

but not emphasized has been the fact that intelligent people, upon hearing a new word, are much more likely to guess the correct spelling (vs. the other category of people). If your problem with spelling is that it is purely an issue of rote memorization, your real problem is likely that you lack intelligence.