Number one, a good pair of shoes
Pay the most you can afford, you really won't regret it, in this case it's no economy to save money. You really do get what you pay for. what you want is either a pair of latchets or some long shoes (also known as startups by reenactors). Latchets were by far the more common type of footwear, but long shoes were also worn we think by soldiers who may have had an agricultural background. They are generally more protective of your ankles.
Number two, stockings.
Number three: Good pair of breeches
Number Four: A Nice Linen Shirt
A shirt made of unbleached linen. It should be cut square and long, front and back each made of a single piece of fabric, gathered into a narrow neckband.
The sleeves are cut square and gathered to a cuff with square gussets under the arms. There may also be triangular gussets where the collar meets the shoulder seam.
At the front there is a simple straight hemmed front opening, secured by a pair of ties. The shirt should not have any more than a small standing collar and a falling band may be tacked on. For common soldiers the band should be just large enough to cover the standing collar on the coat.
Hand sewn linen shirt made by Tricia Webb, photos by Andy