First, and this may seem elementary, but remember to breathe. Take deep breaths when learning new material. Oxygenating the body not only relaxes it, but also increases brain function. Eating a balanced diet and especially a good breakfast are essential for starting out on the right foot.
Read and write. History has taught us that the world's geniuses have always done this, and it makes sense. Reading triggers the brain to create images in our minds and writing requires the brain to think up different images that we want to create. It is literally a brain workout and really helps to increase your IQ.
Never ever quit learning. Become a knowledge sponge. Learn how to pick out the important points and disregard unnecessary information. When learning new things, use acronyms, songs, whatever it takes to remember the facts. Most smart people use these little tricks to retain large amounts of data. Very few of us have a photographic memory.
Work out your brain with mind teasers, brain games or aptitude tests. They actually sell these kinds of games and they will require you to think and hopefully, think outside of the box. That is what seperates an average mind from an above average mind; thinking outside of the box. It's a trick that takes much practice, but the ability to think up ideas that others are unable to will seperate you from the pack.
Lastly, increase your vocabulary until you die. That's right, there is not one single thing that will increase your IQ and make you smarter, or at the least seem smarter than an extensive vocabulary. It's paramount and will gain the respect of others. The average IQ is 100, so do your best to exceed that and people will take notice.