Question 1• I was wondering what I should wear... last time I competed I wore a western shirt tucked into a pair of dark jeans with a hat... this year I'm planning on wearing: white w/ purple/silver/black flowered western shirt, black show pants, black suede and satin vest and a black felt hat (if I can get one cheap enough) does that sound good?
That sounds great! Remember, the devil is in the details. Be sure that the shirt and pants are pressed and brushed to remove all lint and horsehair. Those sticky lint rollers in the pet department are wonderful. Make sure everything fits well, and isn't baggy. You can have the most expensive, glamorous outfit in the ring, but if the fit isn't flattering it won't matter. Remember a black leather belt and boots, saddle soaped and shining.
A black felt hat can be great, but don't discount a nicer white straw model. The straw can be a bit more affordable than felt, and is definitely cooler in hot summer weather. Depending on the rest of the picture, a lighter color can brighten up your face and provide a better impression than a dark felt hat.
question 2• MY horse is a buckskin so I've tried to select colors that compliment her coat. So I picked a dark redish brown leather halter and a lead and chain to match, how does that sound?
That color of leather should be fine on your mare. In terms of color coordination, I really like Hobby Horse's color wheel as a reference.Hobby Horse Clothing Co. - Description
Hobby Horse's products are pricey in general, but the general advice on their site regarding color coordination, presentation, and turnout preparation is very sound and can be really helpful in putting together a fine show outfit on even a miniscule budget - I type from experience, here. ;)
More important than the color of the leather or amount of silver on it is the fit. The throatlatch should be up in the throat area, not hanging past the jowls. The cheekpiece should be parallel to the straight line formed by the cheekbone. Make sure that the chain on the lead is threaded correctly, as rodeogirl noted - there are several other threads in the Horse Showmanship subforum that deal with correct chain configuration in some detail.
question3• I need some help with my pivots (hindquarter). Whenever I try to pivot her she will cross in front about 3 times then step once with her back feet... in order to do a good pivot one back leg must stay planted the entire time... any suggestions?
Remember that you cannot touch the horse in a showmanship class, except to fix/acknowledge the judge inspecting the mane or forelock, so don't rely on hand pressure to get the movement.
One instructor I had recommended backing the horse up a step before starting the pivot, to get the pivot foot farther behind and allow the stepping foot room to get around it. I've seen that method work, and I've also seen it create issues with proper front end crossovers as the horse is thinking "back" not "forward."
What has worked the best for my current horse is to just practice. Get a few great steps, and walk out of the turn before you lose the pivot. Keep it forward - don't just stop the pivot and stand there, move directly out of it into a purposeful walk at first.
You can use your hand or a dressage whip to back up your body language/voice/lead cues, just use it as a final resort to get the shoulders moving, not as your primary aid.
Watching YouTube videos of G&S classes and patterns is wonderful practice. It'll really help you get a feel for how you want to present yourself and your horse.
Good luck, smile, and above all, have fun!!