Select your type of wire. Lower gauges are going to be sturdier, but harder to bend and shape. A 22-24 gauge wire is ideal to start with, unless you're using a particularly heavy material to cover your model.
Unwrap some wire from the spool, using your fingers to bend and shape it into your desired model. Use multiple pieces to add to your structure.
Make small loops in your wire to thread other wire through. This will keep your model sturdy.
Add wire mesh to the larger gaps between the supports, if needed.
Cut the wire from the spool with wire cutters once the wire mesh model is complete. Cover with whatever material you choose.