Throw out any superfluous facts or any merely minor facts that prevent the orderly working up of the group--that prevent or mar the effect you wish to present.
Then, when you've got a group thus presented, go over what you've made of it, to make sure you've used your material and its arrangement to the best effect, taking away merely extraneous or superfluous or distracting facts, here and there adding concrete illustrations--putting in a convincing detail here, and there a touch of colour.
Then go over it for your vocabulary.

See that you use no word in a different meaning than it was used 100 years ago and will be used 100 years hence.

You wish to use only the permanent words--words, too, that will be understood to carry the same meaning to English readers in every part of the world.

Your vocabulary must be chosen from the permanent, solid, stable parts of the language.
Then see that no sentence contains a hint of obscurity.
Then go over the words you use to see if they be the best.

Don't fall into merely current phrases.