I taught this in class nary a day ago. ''Some'' is used for positive sentences. ''Any'' is used for questions and negative sentences. At your level, this is the exact rule you ought to follow.

They can mean the same thing. But the sentence structure may be a little different...will you have some and won't you have any? In these examples they both discuss an amount of something but the amount isn't an exact number or a speccifically known quantitiy. Typically some is used for positive andany for negative statements. I wanted some candy but unfortunately they didn't have any. I don't want any advice, could you give me some advice. Also, sentences don't typically start with any, some people told me is ok...you mighthear asentencelike, any chance you canhalp me, but really it should be is there any chance you can help me. The first one is incomplete but as native speakers we know the 'is there' is understood. This would be a very informal way of speaking and you might use it in writing as part of a dialogue but it would not beconsidered correct or acceptable in more formal writing or speech