Practice. Just write some random things and have someone check it or just post it here and people here can tell you what our doing wrong and how you can improve. Read.
Reading books can also help you with grammar and spelling. Punctuation is really annoying. Just learn the rules off the internet.
I recommend youtube :D. So just read and write a lot. Practice makes perfect.
Google what you just asked. Punctuation: you use a period (.) at the end of a sentence. Comma: when your listing things: I like apples, bananas, pies, and dogs.
There is a title 'English Grammar for Dummies' which might help. You can check others which are close by that one at virtually any retail bookseller.
Read a lot of book's. You'll pick stuff up.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.