If you're on a budget wear a loose fitting gauzy dress in natural color, an embroidered or lacy vest, leather scandals and a floral garland in your hair. Avoid bright reds, fluorescent and other bright colors or pastel shades. These are modern colors. Fabrics should be rough natural such as wool, woven cotton, raw silk, flax, leather and linen. Wearing different textures together creates a good look.
Older children dress as smaller versions of the adults.
Hat's should have a 16th century look to them such as muffin caps, biggins or straw hats. Make a statement with your accessories. Carry a tankard and a pouch. Once you decide who you are make your character visually interesting by carrying the tools of your trade. A cobbler might have a small hammer and awe in his belt.