How to be perfect in English spellings?

You can refer to the following link for the 9 methods of improving English Spelling - finding them quite useful.  Wishing you all the best.

http://www.fluentu.com/english/blog/how-to-improve-english-spelling/

The link provided by Ping Fung is very helpful. I would also say that good spelling is often a matter of visual memory. Therefore my top tip would be to keep a list of words that you find difficulty in spelling correctly and simply look at the list frequently. Try to become familiar with the shape of the words.

Ping Fung's link mentions US v UK spelling. Although I'm British I would say that (to make a vast generalisation) US spelling is slightly easier as it tends to correspond  to the pronunciation a little more. Maybe Noah Webster should take part of the credit for that!

I agree with Brian Pole. It is a matter of visual memory. It  also helps very much if one always looks up the DICTIONARY: ULTIMA RATIO.