I spent most of my time riding English, but I competed in a few western pleasure classes. Whereas English equitation is all about having your horse on the bit and tucked under, western always seemed a bit more laid back to me. you want to have a gentle feel of your pony’s mouth, but don’t let the reins slack too much. sit straight, but easy/comfortably. communicate with your weight and seat mostly, rather than tugging or kicking. (i’m sure you know these finer points if you have been riding for 4 years
the biggest goal is to look like it’s seamless…like your pony just had the “idea” himself to pick up a jog without you even telling him.
other than that, keep your head up, eyes straight. Polish or clean your tack and make sure your pony is clean and presentable as well. (again, you probably know this).
Good luck!

umm…usually they look for posture and control. for the posture part keep you heels down and your back straight.