English Grammar and Composition

How much are you conscious about your English Grammar? How much confidence you have about talking and assuring your sentence built is correct? Do you know what's the rule in English? How about the Subject-verb agreement? when shall I use can and could in a word? isn't it confusing using in, on and at in a sentence??
My English sucks coz I have been grammatically wrong with my sentence. Sometimes I am having doubts to speak! :-/ I also like to learn those American slangs like "get a grip", "word" and etc I have forgot about it. My head aches every time I do not understand what is an article is talking about I just can't understand them and I can't translate it on Google translate coz they are very literal in translating in English to Filipino. However, I appreciate those people who use simple English (understandable) with correct grammar. Im sorry guys if I sound so naïve but I am feeling determined. hehehe.
My English sucks coz I have been grammatically wrong with my sentence. Sometimes I am having doubts to speak! :-/ I also like to learn those American slangs like "get a grip", "word" and etc I have forgot about it. My head aches every time I do not understand what is an article is talking about I just can't understand them and I can't translate it on Google translate coz they are very literal in translating in English to Filipino. However, I appreciate those people who use simple English (understandable) with correct grammar. Im sorry guys if I sound so naïve but I am feeling determined. hehehe.