Here is an example. Place the the word only near the noun. Write: I have only twenty dollars. Don’t write: I only have twenty dollars. If you are having a casual conversation, say whatever comes to mind. It makes little difference.

Here is another example: different. The weather at the oceanfront is different from the weather downtown. One thing is different from another, not different than another. You can put a degree on different—very different—but use the preposition from.

Unique is an absolute adjective; excellent is an absolute adjective. Do not add modifiers. Do not write: That is a very excellent essay. Do not write: She has a rather unique way of looking at the world. Something is either unique or it isn’t. There are no degrees. Something is either excellent or it is, for example, very good. There are no degrees of excellence.

For punctuation, The Chicago Manual of Style is the best guide. About twenty pages in the middle of the book cover the subject, and the examples are wonderful, vivid illustrations. Also, teach yourself to type the m-dash—this one. On my keyboard, it is simply shift+option+hyphen.

For the British, the verb get has evolved. For Americans, it has not. Our usage is not wrong; it is just old. British usage goes: get, got, got. American usage goes: get, got, gotten. I prefer British usage: Recently, the nights have got very cold. However, when I am talking about a crook, I might still describe his wealth as ill-gotten gains.

Most prominent publications have style manuals. You can find one for The New York Times, The New Yorker, and others. I have read the two I just listed. I remember this: In The New Yorker, the word ensure is not used. Insure is the only way to cover that meaning: He buried his money in a hole in the ground to insure its safety.