V for Vendetta

[Andromeda18_]

I think I got most grammer rules down pretty good. I know the difference between they're/ their/ there. But that to and too thing I don't really get. Any easy way to help me remember the difference?

Let me try and help, although I do this in a very instinctive way.
'Too' means:

In addition; also: He's coming along too.
More than enough; excessively: She worries too much.
To a regrettable degree: My error was all too apparent.
Very; extremely; immensely: He's only too willing to be of service.
Informal. Indeed; so: You will too do it!

So basicaly you use 'too' either with the same meaning of 'as well/also' or to express an excess/extreme (though not necessarily with a negative connotation). In the sentence "She worries too much" 'too' is used to show she worries excessively. In "He's only too willing to be of service", the 'too' expresses an excessive willingness to be of service. So, whenever you don't know if you should use 'to' or 'too' in a sentence just pay attention to the sentence and see if either 'as well/also' or the idea of an excess would fit. If they do then you want to use 'too' and not 'to'.
'To' can either be used as a preposition or an adverb. Before a verb in the simple present always use 'to' and never 'too' (to eat, to sleep, etc).
Personaly, I recommend you pay attention to the 'too' instead, it's simpler. If you realize using 'too' doesn't make sense in a sentence then go with 'to'. Of course, like I said in the beginning, I do this instinctively so my explanation might so weird. I don't usually think about which one I should use.