Your bothered by the metal pencil cases too! Your making another common North American mistake, You're not Your.

Everybody has problems in writing and mine is spelling. I tell my students it is one of the biggest challenges in English. It really is. Here in China the spellcheck won't work (too much delay) and I depended on it.

Its and it's is a difficult rule but just remember to use the ' only when you mean the contraction for it is . You never use it to show posession as in the following sentence.

I have the horse but where is its saddle?

The rule is unusual because it has this exception. Nornally we use ' to show posession but not with its.

I had to check that in a writer's guide so many times to get it right.

A very common grammer mistake that buggs me is the misuse of quotation marks. With computers we can bold words or underline, etc.

On a different note: Yesterday I told my best student that languages are much the same (He didn't believe me.) and that nouns and verbs contain the most important information, maybe 75%-80%. Nouns are vital to begin using and language and verbs come later. That is how I approach a new langauge. They don't intimidate me now. He said,"You mean we don't need grammer?". We don't need grammer, not for basic communication in the early stages of learning.