1. Have a good thesis

The thesis is the road map for your paper. Your thesis should pave the way for your paper. If your thesis goes 1 2 3 then your paper goes 1 2 3. If you can get your thesis to work and be the road map that it should your paper will fall right into place

2. Read your sources and read them correctly 

The first part of this should go without saying but I'll say it anyway. Read your sources for your paper. If your professor says to write a paper using books X and Y, read X and Y. Now a little trick to actually reading those books.

If the book is an analytical book then read the intro and conclusion of the book thoroughly, the middle can be skimmed. Historians but the bulk of the important parts in the intro and conclusion.

If the book is a story then you'll have to suffer through it.

3. Don't wait till the night before 

This is true of all papers so I'll add it in. Some people can work great under pressure, a lot of people can't. Don't spend the night before writing the paper but instead edit the paper.

4. Use Google Translate

Speaking of editing. Use Google Translate to edit. I can hear some of your confusion as I write this. If you copy paste parts of your paper into Google Translate and hit the listen button. It will make errors very clear that you might otherwise miss. It also helps detect sentence flow which can help.

5 Do not use contractions 

This one depends on the teacher but applies to most. Contractions are a big no no in history papers. Lots of contractions will turn a once A grade paper into a C grade paper real fast. So avoid them like the plague