Most important....
Self....
I would say this is the most important thing. You must be cleansed, confident, positive, FOCUSED.
You need peace/not disturbed by anyone. As with all casting you must be prepared mentally/physically (not ill)/emotionally.
Note: Never cast when angry "Be careful what you wish for".
And remember casting and alcohol don't mix. EVER.
IF YOU DO NOT BELIEVE WHAT YOU'RE DOING WILL WORK....THEN IT WONT.
99% WILL 1% PROPS
If you're ever in doubt, go with what feels right, be inventive, let go of constraints and free yourself from conditioning. Dance if you want to, sing if you want to, chant, pray, meditate, be free. The more personal it is to you the better it will work, remember what you read in books etc. is what worked for that person. I would say it can be followed as a science but like your dreams etc. things mean different things to different people.
It's your rite, do it your way.
Have faith in yourself, in your own ability, the power is within you, it's not in the universe/astral planes/gods or goddesses. The power/energy needed to make magik work is within you. This is because the power of the universe/the architect/god/goddess/earth is within you.