Spontaneous recall

Especially with small children, memories simple appear to surface from nowhere. Some describe the process as being like a "waking dream". Images and scenes may come to mind and the subject may often find themself as a participant in the memory, though often they report feeling somehow different in the memory from their current self. Although it might seem like a daydream, the subject is often surprised by the unexpected nature of the experience and it can also be very intense.

Triggered recall

The memory is experienced in the same way "waking dream" fashion as with spontaneous recall, but it is triggered by an event of some kind. This event may be anything which appears to remind the subject of a key part of the memory - for example a particular smell, the sight of an object, a noise, hearing a particular word or phrase, a taste or being in a particular physical setting.

Dreams

Sometimes people have recurring dreams which do not seem at all to be the usual surreal type of dreams, but which have recurring scenes which seem strangely real. The vividness can vary from a dream which is thought-provoking to one which leaves the subject in a cold sweat or in tears.

Hypnosis

Profound meditation

Profound meditation is said to be able to give some subjects spontaneous memories which appear to be from past lives. Once profound meditative states can be achieved, the effect is similar to being under hypnosis, except that there is no strong external influence over the subject. The difficulty of this approach is that is can take years of intense meditation in order to perfect a particularly deep trance and even then there are no guarantees. Having said this, people who experience past life flashbacks or fleeting memories often appear to have a head start in this area, and can obtain results fairly quickly if they persevere.

It is worth noting that for thousands of years it has been the single most common method used by people of all religions or philosophies in order to gain mystical insights.