Old Time New Time
When people are young we call them children. Children think time drags by slowly, every day lasts a lifetime, every moment is almost tangible in its slow passage. Keep a child waiting in a queue and they get bored so quickly.
As we get older time seems to accelerate. Time flies by. This is because our perception of time slows down.
When brains are young and fresh they collect information very rapidly, the internal clock ticks at a high rate.

Our perception of the world does not happen at a fixed rate.
Time 'feels' like its going faster and slower, depending on how important the sensation of our environment is.

Think of a film camera. It takes 24 pictures in a second. If it takes 40 pictures in a second and then those pictures are played back at the normal speed of 24 pictures a second then the pictures seem to move slower. Take fewer pictures per second, say 15, and play back all the pictures at 24 pictures per second and the pictures seem to speed up.

As we get older our brains take fewer and fewer 'pictures' every second. This is not because of the effect of aging, but because on the relevance we perceive our surroundings to have.
We are only aware of what has happened in our memory, where the 'pictures' are being played back at the regular rate. So as we get older and the internal camera seems to get slower and time appears to speed up.

This is a common phenomenon felt by all aging people.

The Temporal Soup
Some drugs affect a person's perception of time, because they affect the mechanism of the internal 'camera' - that collection of energy receptors and their interpretation by the brain. I would not recommend chaotic alteration of the brain's time perception. Rather, one can influence the naturally occurring drugs in the brain to alter time. Stir the Temporal Soup.

How to Slow Down Time
Ever been in an accident and it felt like time was slowing down? This is because your internal camera went into adrenaline overdrive and took more pictures per second than normal.

The human brain is a self-balancing system. Too much adrenaline and the brain balances out, making your average thoughts and pictures much slower. You can use this in the opposite.

To counter the time-aperture effect and to feel like the days aren't rushing by you need to relax your brain. When your brain is completely relaxed and healthy it starts to take pictures at a higher rate, and becomes more focused. You can practice time dilation by focusing on something mundane.
Traditionally some monks spent hours focusing on a candle flame without thinking a single thought. This re-trains the mind to process quickly, subconsciously, to take in a lot of information, because the information is perceived to be rare and valuable. When you rely on your slow consciousness your perception becomes slow too. What is reflex but a faster processing of information by the subconscious? When you see everything around you as being rare and valuable your mind speeds up and your perception of time slows down. You use your subconscious more, the faster internal processor.

Everything that exists is important, give it your full and focused attention. When you focus your attention on a being, the tiny nuances of that person become valuable to you.