(1) Travel close to the speed of light
The closer to the speed of light you travel - in other words the faster you go - then the less passage of time you experience relative to a slower moving frame of reference. Put simply, if you were to get in a really fast spacecraft and zoom off through space, then when you come back to earth you will have aged less during that time than the people stuck on the surface of the planet. How much depends on how fast you have been going. With current technology the speeds we can achieve would have no meaningful impact. But nevertheless the difference is there, it is just very small. If however you could somehow travel very close to the speed of light, say 99%, then the effect would be profound. If you were to go and travel for a year as measured by yourself at 99% light speed and come back to earth, then whilst you might age from 20 to 21, someone else who was also 20 would now be 27 when you arrive back. You have only experienced the passage of one year, that they have experienced much more. This is science fact, and has been observed in practice in many ways. For instance some cosmic rays result in exotic particles being created with very high speeds when they hit the earth's atmosphere. Some of these should decay in, let's say, a second. However due to their travelling so fast and the effect of time dilation, they have been observed not to decay for several seconds by us (humans!), as they are travelling at such a high percentage of the speed of light.
(2) Accelerate, but really fast, and continually!
If you continually experience acceleration, then you will also experience the passage of less time. What is particularly interesting is that this is equivalent to the third and final option to be discussed here, which is listed below, hence more details there.
(3) Go close to a black hole, but not too close!
The point of this one is to experience insanely high gravity. In the presence of an extremely high gravitational field such as that around a black hole (assuming just for this that you could of course avoid getting sucked in), then time will also slow right down. So if you could experience such an intense gravitational field, then in effect you are time travelling relative to everyone else because whilst they may experience the passage of many years you would experience the passage of barely any time. What would this look like? Well to anyone travelling past in a spaceship at a safe distance well away from the intense gravitational pull, you would either appear stationary, frozen in space, or moving extremely slowly, depending on how close you are. It is interesting that this is equivalent to 2, due to the equivalence of continual acceleration and the presence of a gravitational field, for which you would need to read about general relativity to find out more and the simple thought experiments that can be performed to help understand this.