Stop when you are told to stop. A good test score means that you followed directions and marked the right answers. A poor test score may mean that you just didn't follow directions. On some tests, you mark your answers in the test booklet, but on most tests you mark your answers on a separate answer sheet. Don't give up.
Some tests are easy.
Others are hard. But DON'T GIVE UP just because a test has a lot of hard questions. It's probably just as hard for the others taking the same test. As Your Head On Some Aptitude Tests Not all aptitude tests are paper and pencil tests. Some have you work with your hands.