Rather a late response, sorry. So, by the fourteenth century, the Scottish nobility was not dressing differently than the English (and French) nobility - far from the stark difference in material culture that we see in Braveheart.

This is actually quite an interesting period in fashion history. At the outset of the century, men's and women's clothing (cottes or cotes) appears to have been rather loose and unshaped; the tailoring techniques we take for granted, like set-in sleeves, weren't in use, and neither were the lacing or fastenings needed to make a tight bodice able to be put on and off. This is "before fashion", when dressing to impress meant making use of the best and most expensive fabrics in lavish lengths, rather than conforming to the newest cut or construction. This type of clothing is fairly easy to sew - the pieces are generally rectangles with minor modifications, which is also economical and results in little wasted fabric. Here are two thirteenth-century stained glass windows at the Cloisters that show what I'm talking about - King Louis IX and Woman Dispensing Poison; as you can see, the basic gown of men's and women's clothing isn't really gendered. You would generally find more differences in other aspects of dress, like hairstyle/headgear, or slight differences in skirt length.

By the middle of the century, however, we're in what's sometimes called the "tailoring revolution". The shaped sleeve and armscye allowed a closer fit in the shoulder and upper arm, while buttons and lacing down the front or sides allowed the bodice to close in on a defined waist. This was rather wasteful of fabric, since more dramatic shaping to the pieces meant that they wouldn't fit together smoothly on the flat fabric, and therefore more scraps would be generated. We also start to see changes in cut and fit that indicate differences in social status and fashionability. The most fitted garment, worn directly over the body linen, was the cotte/cote, often layered with a slightly less well-fitting surcote (by definition), and a mantle/cloak/outer wrap could be worn as well. As I discussed in this previous answer, part of this "tailoring revolution" also involved fashionable young men adopting short-skirted cotes along with hose joined with a codpiece. And at the same time, the houppelande was introduced - a voluminous, excessive, sometimes fur-lined garment to be worn with a belt over the fitted clothing, generally with sleeves that were either gathered at shoulder and wrist or else slashed open and worn trailing. In either case, it was a sumptuous display of wealth and style.

For more reading, I would suggest Odile Blanc's "From Battlefield to Court: The Invention of Fashion in the Fourteenth Century" in The New Middle Ages: Encountering Medieval Textiles and Dress (2002) - which is a good book to have in general if you're getting into medieval fashion - and the less scholarly Fashion in the Age of the Black Prince: A Study of the Years 1340-1365, by Stella Mary Newton (1999). And if you haven't started sewing yet, The Medieval Tailor’s Assistant is probably a good place to start for construction (although as with all reenactment sewing instructions, there are controversies).