Average ladies wrist size is 61/2" to7". I create 7" bracelets using wire wrap or stringing beads. In almost all my designs I will finish pieces with jumprings so that they can be enlarged easily or reduced. Don't base your bracelet on your own wrist size unless it is one of the above measurements. Again use jumprings in the closures or ends so that you can remove or add to adjust sizes. At shows carry extra jumprings and tools to adjust for your buyers.

If you're using "Stretch Magic" or any stretchable beading material, the average size wrist is 6 1/2". If you're using chain or standard closures (such as lobster clasps etc) make the syle adjustable. See my inventory at www.amarettejewelry.com. I hope this helps!

Use stretch magic stringing and you won't have to worry about the size

It is hard to come up with a good size of bracelets to sell to others. The best size is about 7in to 71/4in in a bracelet to give and sell to others. Also you can custom make jewelry for your friends by having a tape measure with you so you can measure their wrists and write their measurement down so you can always have their wrist size as you don't have to measure their wrists again.
Also it is best to have a EZ bracelet sizer to come in handy when measuring custom made bracelets and you can buy this on artbeads.com.
And if you think if the size of the bracelet looks to big or to small for the measurement, get the bracelet down to that measurement as close as you can.
Sometimes stretch bracelets is a good start to sell because they can be one size or two as they strech over the wrist very snuggly and just right.

Seed beads are glass and are small.

Seed beads are made of glass when a long tube of glass is made and cut into small pieces and then tumbled to make the seed beads.

The higher the number the smaller the bead. So for something tiny I think size 15 Japanese seed beads.