For many the prospect of having to sit a number of aptitude tests, sometimes even before you get to have an interview, is a scary prospect and may even put you off completely.
I have worked in the industry that creates these tests for over 10 years and was faced with this exact same dilemma when going for my first interview. I almost did not go and if I had not my life may well have been very different.
Firstly, don't panic, stay calm they are not as bad as you might think. If you approach them in a practical way you will probably do a lot better than you think. The level of the tests will be aimed at the job level and expected educational / experience level so if you are applying for that job you should already have that sort of knowledge and skill right?
Secondly, practice, practice, practice. If the company is following suggested guidelines they should send you some practice materials which show the style of the test(s) and allow you to try some sample questions. If you are doing something online there will often be practice questions first but still better to practice before you are about to do the real thing! Even if you do not have these you can practice reading information and analysing it and studying numerical dta and interpreting the results.
Thirdly, never, ever cheat. These tests have sophisticated checks to ensure cheating is not possible. If you are completing a test online it may be tempting to get someone else to do it. Sure it gets you to interview but you will probably be tested again and made to look a right idiot...
Tips! A lot of the tests are scored on your total number of responses. You should try to complete the test quickly and as accurately as possible but do not spend too long on any one question.
Many test providers offer practice tests and information online that you can complete or download. Saville Consulting, offer some great advice and practice leaflets to download.
Overall do not be afraid, these tests are a very good indicator of job performance and if you spend a little time familiarising yourself with the format and style you should be fine.