There is a good thread about the Quarter Method here: The Quarter Method
Remember that in a SHOWMANSHIP class, grooming AND presentation count, so you're being judged on the whole picture -- how you complete the entire pattern and how you present yourself and your horse (with confidence, and a SMILE helps!) counts, as well as having the horse groomed to within an inch of her life.
In a HALTER class, the horse is judged on conformation and suitability, so all the elbow grease and showsheen in the world won't help if your horse is not the right type!
Another note, though it's been a while since I've shown western, so someone else may need to chime in -- I believe if you use a stud chain it's supposed to go under the chin instead of over the nose.