Your IQ is just a number, not a measure of your worth. But IQ tests are often used by admissions and hiring departments as a way of measuring potential, so if you're going to take one, you want to score as well as you possibly can. Consider some advice and techniques that are proven to be helpful.
Prepare Your Equipment
You've probably heard since childhood that you should eat right, exercise and get enough rest. All of these factors will help ensure that your brain is at its best on the day of your test -- if you start tending to them at least a couple of weeks beforehand. Eat whole grains, fish (for omega-3 fatty acids), and fruits and vegetables that are rich in B vitamins. Practicing a simple form of mindfulness meditation can be invaluable to help you focus before and during the test.
Understand the Test
An IQ test is designed to measure intellectual functioning in itself, not knowledge. You won't have to remember facts. IQ tests measure visual-spatial processing, aural processing, working memory and processing speed, usually by using a combination of multiple-choice questions, pattern recognition and logic puzzles, and math problems. If you can find out in advance what test you will be taking, you can find a lot of information and maybe even some practice tests online.
Fine-Tune Your Brain
Strategy-based games, such as chess and Stratego, and number puzzles, like Sudoku, can help you sharpen your processing skills. Practice spotting symmetry and patterns in your everyday surroundings. Opt to read or do puzzles instead of vegging out in front of the TV. Read material that challenges you, and look up any words that are unfamiliar. Get outside your comfort zone: Take a new route to a familiar destination, or take up a new skill.
Get Some Practice
You can find countless IQ tests of varying degrees of difficulty and accuracy online. Some are worthless, but others contain the types of problems you'll be expected to answer on an actual test. Familiarize yourself with the types of pattern recognition, "set completion" and multiple-choice questions you're going to encounter, and take one or two practice tests a day.
Raven's Progressive Matrices, a well-respected test that's been in use for decades, are available free online. IQ Test Labs offers sample questions testing verbal, mathematical, spatial, visualization, classification, logic and pattern recognition, as well as a practice test and a selection of mind games and puzzles. The international high-IQ society Mensa also offers a free online "workout."
Play Dual N-Back
Researchers affiliated with the National Academy of Sciences found in 2008 that subjects who played some form of a game called dual N-back increased their test scores compared to a control group. The game trains working memory by asking players to identify re-occurring match-ups of auditory and visual cues. A version of Dual N-Back can be played for free online.