'A picture says more than a thousand words'
It is scientifically proven that people's levels of intelligence are mainly based on their genetic predisposition. The level of general intelligence cannot be altered later in life. What can be improved, though, is the performance of your brain. Scientists have found out that the human brain can be improved until late in life. This is called neuroplasticity.
To improve the performance of your brain, you can use different techniques. One of them is called the 'Loci Technique' which can be used to memorize e.g. the storyline of an important presentation. It brings your content into a fictious structure.