Do you have any advice on how to write and revise better history essays?
The first thing that you need to do is to plan. Find out exactly what your teacher wants--this could be a biography, a retelling of events, or an analysis of a movement. Also, make sure you are clear on how many sources to use and the length of the assignment. Also, know the citation method (MLA, APA, Chicago) style the teacher wants. Get started early with your research and writing--do not procrastinate. Pick a topic that interests you, and find as many sources as possible. Use primary sources--material written by people from the period. When checking the value of sources, be aware of bias--many times an autobiography may present the author in the best possible light, but will not give you an objective view of the person. Write a good thesis statement (one that can be proven) and make an outline where you create your supporting evidence. Cite anything that is not common knowledge. Stay away from commonly used phrases such as "in conclusion," and do not ask rhetorical questions. Also, do not say "I think...." or "I believe..." since this is your essay, and you should think and believe everything in it based on the evidence you have gathered.
In terms of revision, read your own essay, preferably a day or two after you have finished writing it. Also, if your school has a writing lab, make use of that resource and get another set of eyes to proofread your paper. After you are sure the paper is free from grammatical mistakes and the thesis and supporting evidence are strong, you are ready to submit the paper for grading.