The loop on a small glass bead or even resin should be based on the size of the bead size, since you will be working on small beads that breaks easily for its size the sizing of the loop should not go bigger than the size of the bead.
Establish the loop shape and size from the size of the bead. Place the wire at a point on one of the prongs of the round nose pliers closest to the bead size. Bend the wire 3/4 from the tip following the curve of the nose plier prong.
Keep the place to where the size of the loop for the bead would be. Use the nose plier's points and level them to each other. This will be the indentation points of the loop.
Create the action of pulling down on one side of the wire from one of the indentation point of the wire for the loop.
Create this same action to the other side of the wire to make a shape of a loop similar to a "key hole".
Gently holding on to the loop with a flat nose pliers, create an "L-Shape" with the short wire going on top cross and the longer wire going to the bottom. Do this same step on the other side.
Creating the wire wrap should be the height of the bead half way. This will establish a balance between the bead and the wire wrapping.
On a small glass bead it is important when cutting excess wire to always cut against, closely to the wire wrap. Do not force to push the wire, to prevent the bead from breaking when flushing the edges of excess wire.
On any type of beads flushing the excess of cut wires are the same although with small glass beads an extra care and handling must be applied. Done on both sides of the beads gently press on the excess cut wires with a flat nose pliers, it is important to keep in mind not to make your movements tight, always imagine the malleability of the material is equal to clay.
Keep in mind when wrapping glass beads and in general that wires move like clay, and the pressure you apply to it should be similar. This "Clay pressure" like approach would provide ample movement for wire and bead to move when finish a wire wrap.
Be able to wire wrap small glass beads