how to get grammar mistake while writing mail.?

To have a teacher to correct your English writing, of course, is the best way to learn grammar. But there are still some methods to improve your(my) English writing. My method is as follows.
I’m retired and I’m still learning English as a hobby and answering questions on this website (focusing on Chinese questions. Because I’m a native Chinese speaker and an English learner). When I lack confidence writing a sentence properly, I type a partial of it, normally 3 ~ 6 words, into the input box of Yahoo Search (ex: into the input box) to check if there are many sentences just like what I’m going to write. If so, I can relatively say my sentence is normal. If I can’t find any sentence on this website, Yahoo, NYTM, etc., then I can guess my sentence might be illogical and need to be corrected.

Learn grammer of ur language from a teacher , it is the only way to correct it