You've understood it it if you'd already watched "Sherlock Holmes" or heard an idea about the Greek methodology of "Loci" its some sort of Mind maps.
Its working depend upon your capability to use your senses; by senses i mean not just six one but all those you can develop by working own your consciousness.
So, now you may think its just useless , time wasting or just having no worth at all .

Choose a smart blueprint for your palace : this first step is quite obvious , as heading clear it first you have to choose a place which you wanted to filled with info or stuff which you want to remember.
A basic palace could be your bedroom, for example. Larger memory palaces can be based on your house, a cathedral, a walk to the corner store, or your whole town.

Place thing that You want to remember in place: Now I've already choose your place now a time to start putting information into the separate places.
The images you put in your palace should, obviously, be as memorable as possible.
Generally, images will be more memorable if they are absurd (out of the ordinary), or if they are attached to some strong emotion or personal experience.
Stock your palace with other mnemonics : its a lot easier to use mnemonics to put in your Mind Palace so use it, As an example, suppose you need to remember a great deal about music composition which is just for example (EGBDF).
As you enter your kitchen, you could see a little boy eating a piece of chocolate fudge, which would evoke the first-letter mnemonic “Every Good Boy Deserves Fudge," which would in turn allow you to recall the order of notes on the lines in treble clef (EGBDF).
Personal Experience :
>i tried to built up whole palace of my own but its hard to made up thing with precise vision .
>Its lot easier to try it on things which already exist.
>Be a Good observer so you'll enjoy its full taste.
>I hope sooner i'll built a Medical Palace :) for by med info stuff.