Like open-book and open-note tests, take-home tests are usually more difficult than in-class tests. Read the directions and questions as soon as you receive the test to help you gauge how much time you will need to complete it. Remember that your teacher will expect your essay answers to look more like assigned out-of-class papers than like the essays you would write during an in-class test.
Unfortunately, issues of academic honesty can arise for take-home tests. If you are accustomed to working with a study group or in a learning community for the course, check with the instructor in advance to determine if any type of collaboration is allowed on the test.