The basic rules of English grammar stay the same mostly, except of course for exceptions.
The vital aspects of rechecking your writing needs to be remembered always.
This is the only way you can give across a good impression of error free work.
The nuances and dialects of English are various and by no means, a simple thing.
That is it's beauty.
Writing, reading and speaking it are the various different aspects of it and all need to be mastered.
You cannot do one better than the other or neglect any one part.
Learning it in childhood from your parent, especially the mother who makes an effort to speak or, no matter what the mother tongue of the child will go a long way in ensuring that the kid grows up to be proficient in the language.
The family does need to realise this.
Speaking it in schools, colleges among friends and family, foremost are the various and first way to get this done.
Making mistakes are part of the learning process.
Checking up with a dictionary to avoid wrong spelling will help make it a well proofread write up.
While at a job interview, there is a huge difference one can make and create a big gap between one and one's competitors by just having a good diction, that is error free. Getting training with a good teacher for this will help immensely and make a huge difference in your work.
A well written bio, all other office work letters etc needs a solid foundation of good English of which grammar is the cementing force.
Make sure then that this factor is taken care of.
Whether you are writing for a magazine, book, office work related posts, class work as a teacher, a student assignment or an official letter, your grammar will be the final grading you have in the eyes of your critics.
Make it perfect, as soon as you can, in the best way you feel and in a way that will work out well for you.
Your overall progress in your field of work, or occupation, whatever it is will depend on this.