Here's the general approach to Sigil Magick, as it was created by Austin Osman Spare:
You formulate a statement of intent, like:
It is my will to get a well-paid job
It's best NOT to use the negative form, like "I don't want to", or "that this doesn't happen" etc.
From this letters you form a sigil and/or a mantra.
Now you have to charge it. You can use various forms to do so. Methods range from orgasm, meditation, spinning, chanting and use of drugs.
It is important to forget the original wish after it has been fired off.
A new method
As usual, you formulate your wish, but instead of creating a sigil of it, you sit down and communicate with your sub-consciousness. The task of the sub-consciousness is to create the sigil for you. You then charge it.
How to communicate with the sub-consciousness
First, sit down comfortably and calm down. This is best done with some breathing exercises. As soon as you're calm and in a light trance, call the sub-consciousness from within you to manifest in a specivied part of your body with a certain feeling like warmth, a twitch etc. Continue this practice until this feeling is intense enough.
Then go on to ask the sub-consciousness to show you some reactions for
You can also use this for divination ;) After you can perform this exercise at will, you're ready to start using this method to create and charge sigla.
You create the wish as usual and then you get into your trained asana and invite the sub-consciousness. Then you present it the wish and ask it to create a sigil, what that wish represents for it, for you.
To see if the wish is acceptable in general but still too fague, you have to agree with it to show you a circle around the sigil. The more you see of the circle the better is the wish formulated. As soon as the circle is closed, the sigil is ready to cast.
You should cast the sigil right after it manifested before your inner eye completely. You do this by feeding it with energy.
Imagine a white line coming out of your solar plexus and flowing into the sigil. See, as it starts to live. Then remove the link to you and fire it off.