I love to work with deco mesh. There are so many things you can make with it for the various holidays and it comes in so many colors and patterns. It's also relatively inexpensive if you shop wisely for it. Here is what you need to make a wreath this size and fullness.
A 24" work wreath, 21" roll of deco mesh, additional ribbon and embellishments of your choice. The work wreaths and the deco mesh can be hard to find, at least in my area. I usually end up ordering it online. This is a good site to order the wreaths and mesh from: http://www.mardigrasoutlet.com/. Their pricing is good, the only downfall are the shipping charges which are a little high. I get the additional ribbon and embellishments at Hobby Lobby when it's on sale and even at the Dollar Tree.
To start, take one end of the mesh and twist it, then place it in the twist tie of the wreath and twist that around it several times. Make sure to twist it down good.
The work wreath has two rows of ties on it. One on the outside and one on the inside. Work your way around the wreath alternating between an inside tie and an outside tie. Gather the mesh up in your hand about 9 inches and twist it once, then place it in a twist tie and secure it. If you are new to using deco mesh, it has a mind of it's own. It will twist and go pretty much where it wants to go so don't try to force it in a certain place or shape. The beauty of it is, that is knows how to shape itself. Once you are finished with the entire wreath, you can pull and place the ends into shape a little, but don't manipulate it too much.
See how it makes it's own poofs and swirls. This roll of 21" mesh should finish a 24" work wreath just about perfectly if you space it correctly. If you make your gathers too loose or too tight, just undo the twist tie and start over. After you make the first one, you will have the knack of it. Once you have the mesh secured all around, you can attach a big bow made of coordinating ribbon, weave ribbon through the wreath by attaching with the same twist ties (they are fairly long), you can hot glue ornaments or beads. I hot glued a lightweight USA sign that I got for a $1.00 at the Dollar Tree on this one. Just use your imagination.