When preparing to write out your own spell, make sure you write out a list of these things to consider before starting:
-- Intent - this is the core of your spell. Without visualization of your intent, the focus that comes with meditation, you really can't create a successful spell. With intent, you can put as much or as little as you like in your ritual. As long as intent is there.
-- Knowledge of oil and herb magickal properties - this plays an important part since there are so many different oils and herbs for many, many different intents. For example, van van oil is used mostly in love spells. Five finger grass can be used for protection, luck, and money...and so on. Know the basics or get a list with the names and properties so you can find what you will need to add to your ingredients.
-- What gods or goddesses will you invoke (if any)?
-- Are you going to invoke the elements as well?
-- What will you chant or pray about? Do you have something already written?
-- Don't forget to add the types of candles used
-- List the planetary hour and day along with the lunar time the spell should be cast.
-- Just be sure you have everything covered and remember to add those little details even if you don't think they're relevant. It may help someone else who doesn't necessarily know what to do.
-- Close out your chant or prayers with "so mote it be". I'm even guilty of this from time to time.
-- Just remember that spells are basically patterns. You just need to use the right ingredients. Try your spell out for yourself...how does it work for you?