When you are citing another author's text you should always indicate exactly where the evidence comes from with a reference, i.e.
give the author's name, date of publication and the page number in your work.
After the introduction add further paragraphs to build your argument, make the most important points first.
Remember the way these points are ordered makes your argument clearer to the reader. If you refer to an important historical event, you must make a point or comment about it.
How much evidence you use depends on the type of essay you are writing.
If you want a weight of evidence on some factual point, bring in two or three examples but no more.
Sum up the main points and briefly restate your argument.
Re-read your work, check for spelling errors, and redraft if necessary.
Use these as your research base but try to expand on what is said and read around the subject as fully as you can.
Always keep a note of your sources as you go along.