How Can I Improve My Grammar Quickly?

If you're working on a computer,say in Word,a good start would be to run the spelling and grammar check and always take a good look at the kind of mistakes you're making - are they plural forms? Incomplete sentences? What if you're not sure what you're doing wrong? In that case, the best thing is to find out some of the more typical errors and check your work for these.
The underlying problem with most incorrect grammar is people not really thinking about what words mean. So you get a sentence like "Your my best friend"; if the writer thought about it ,they would know that couldn't be right because "your" means "belonging to you" as in "your jacket." It has to be "you're" as in "you are." You can avoid a lot of errors if you always ask yourself, "What does this really mean?"
There's an amusing list of "errors that make you look at stupid" at insight.znet.co.uk

When i grow up, i will have a nice looking wife

Advise me of the position you're occupying

Read a lot in English, and it will pay off