How to make it - getting started
I'll try to write them as clearly as possible. Should we refer to the wreath as an actual flower wreath? Just to make it easier for me to describe...

First, the making of the flowers/buds/stems. Think natural/chaotic, as would mother nature. There is no 'formula' in which beads to string and/or their order.

1. Cut a string of wire about 5 long 6 inch long and bend it in the middle (not too much, just for an arch to form) and string in several small beads (anywhere from 1 to 6) different sizes, colors and textures do for as many variations as you want. The small beads should be stringed "single", that is, with only one wire
2. String one (or two or three) bead (s) to the bent at the middle of the wire, pull it and twist the wire so it becomes the tip of the stem. Keep the beads close together and twist the wire tightly so there's no left over space and a shape can be formed. Do this with all other stringed beads.
3. String a large bead (crystal, pearls, etc) 'double', that is with both wires at a time (since you have both the moment you bent the wire) push it up to where the other beads finished
4. String another set of beads (1,2,3,4 or 6) 'single' again. And twist to secure beads as desired
5. Twist the rest of the wire

note: use the number of beads to create different stems. For my wreath I alternated between 'long beginning'-'large bead'-'short ending', 'short beginning'-'large bead'-'long ending', 'short beginning'-'large bead'-'short end', and so on. 'short' meaning from 1 to three beads, and 'long' meaning more than four. I also alternated long stems with short ones, short ones giving more body to the wreath, while the long ones help for an airy look. Later on, since it's all made with wire, you can twist the steams as you like for different effects.

these are some diagrams that might help

._._;..o.. _____

.o.._..._. _____

._.o.._____

.o.._____

. = small/medium beads
o = large beads
__ = twisted wire

How to make it - putting the wreath together

 Once you have a handful of stems, you can start putting it all together. How many you need will depend on how big and full you want the wreath to be.

1. Start by taking a few long stems (about 2-3) and one short stem and twist them together, one by one. Twist the 'leftover' wire each of the stems have, together, going clockwise
2. Secure the ribbon (1/16 to 1/8 inch recommended) to this small arrangement either by twisting it into the wire, or using a knot. leave about 6 inch to tie up the ends afterwards.
3. Start wrapping the wires tightly with the ribbon, going counterclockwise. be sure that the beads are tied securely to the rest at the 'base', using the last bead of the stem as the point where to wrap with ribbon, so no wire is exposed in that end. This will serve also to give the wreath strength and body.
4. Add the other stems, one at a time, twisting the wires clockwise and wrapping with ribbon counterclockwise. Arrange the stems so you have a constant variety along the whole wreath, and check the width of set of the wires, so it keeps even (at first it will grow, given you're adding more wire, but up to a fourth or less of the wreath, the width should keep constant) It's almost sure that as you go along the way, a natural curve will from, keep the stems going 'out' of the curve, so the better side is out to the seeing eye, while keeping the inner curve with only ribbon. Remember to keep it tight. Take breaks once in a while, since your hands can become real soar with this kind of work.
5. When you reach the desired length (check on the diameter you want, every once in a while and check it with your head until you reach the kind of fit you want) twist and wrap all the wires that are left after you fixate the last stem tightly until most wires have about 1/2inch left. Twist and bend wires, then wrap them tightly so that the ribbon won't loose itself. In my case, I made a hook so that the wreath might be adjustable (just in case my head gets bigger )
6. Tie the ends together, using the last inches of just wire and ribbon wrapping to serve as 'base' for the initial, lighter stems, hiding the plain ribbon and wire under the stems. You can tie them up with the same ribbon and tie a knot at the end, or use another section of ribbon.

And there you have it. Arrange the stems the way you find best, open them, twist them, or leave them close together. If you tied the whole thing tightly, you should be able to modify it as many times as you want.