Sketch out your design.
Determine what beads, if any, you want to use for the project. If you are planning on using beads, then the gauge wire you chose will depend on the diameter of hole in your chosen beads. For example, freshwater pearls are drilled with a very small hole. 22 gauge wire and 24 gauge wire are most often used when creating wire wrapped jewelry with freshwater pearls. 24 wire gauge is useful for beads with very small holes like gemstone briolettes.
Evaluate the use of the wire when deciding wire gauge thickness. For example, 20 gauge wire is well suited for making ear wires and posts for earrings. Larger gauge wires tend to be uncomfortable in pierced ears and smaller gauge wires are not strong enough to support most earrings.
18 wire gauge and 16 wire gauge are good general purpose wires for most wire wrapping projects. 16 gauge wire is particularly well suited for wrapping glass beads with large holes.
14, 12 and 10 gauge wire are heavy gauge wires that are useful to create soldered rings and cuff or bangle bracelets.