Writing spells usually works, its more about how you are feeling. Its pretty amazing actually.
Whenever i am on road, i keep casting spells on the signals.
"Will of the witch,
So mote it be".
i keep staring at it and concentrating it to be green. Most of the time it works.
Also, another one is with small situations. I visualize it properly, and i say the above thing. Be confident, and it works. :)