The first step is to write your non-ambigious intention down. It has to be as clear and precise as you can make it. Once written down, morph and merge the letters in the words to create a symbol. Put the sigil away and forget about what it means. The easiest way to do this would to make alot of gnostic sigils at one time. After the meaning has lost, look at the sigil during a period of gnosis and burn it into your head. The easiest way to do this, is to look at the sigil during a point of orgasm.
The meaning of the sigil is forgotten by the conscious mind, however, the subconscious mind retains the meaning of the sigil. During the temporary phasing out of the conscious mind, the conscious mind is able to use the sigil and activate the "magick" behind the intent of the sigil. As previously mentioned, most magical and psychic abilities are belived to work through the subconscious mind.