I'll assume you already know some basic techniques and terms (like "seam allowance", "darts", the fact that you have to sew two pieces of material right-sides facing each other then turn it inside out…) If you don't already know these, get someone who does know to help you. I don't want to spend too much time talking about that.
Understanding the Pattern
The pattern comes in a few pieces on cardstock paper. Seam allowance is not included. Trace the pieces onto your material with chalk, then when you cut them out, cut a ¼ inch or so away from the chalk to give yourself seam allowance. This ensures much more precision in the finished product as it's essential that you sew along these lines to make all the pieces match up properly.
Pieces that say "x2" on them (most of them do) need to be cut out twice; once face up and once face down.
The head is the most complicated part of the doll (8 pieces in all, and even more if you decide to sew your hair into the head as you make it), so keep the pattern templates handy when you sew the pieces together. The notes on the pieces will help you determine how the pieces fit together.
The template for the eyes I included is for generic anime-style female character eyes. You may want to make your eyes bigger or smaller or shaped differently, depending on what style of anime your character comes from.
Understanding the Material
I like to use skin-colored flannel for the body and head, but note that if you intend to give your doll "hair", you may want parts of the head to be either the same color as the hair you plan to use or the same material you plan to use for the hair (I explain this more in detail later).
For the eyes, I use a sturdy white that doesn't fray easily. Note, fabric pens are used to draw the eyes, so a fabric that won't bleed the pen is also a must. A closed mouth can be drawn on with a fabric pen, or an open mouth can be pink broadcloth that has been fray-checked.
For the clothes… just use whatever scraps you have lying around. Or, if you insist, get some nice cheap broadcloth. Felt is also nice to use, since it doesn't need to be hemmed.
Stuffing… yeah, get your basic stuffing to stuff the dolls. And be sure to stuff them as tightly as possible.
A note on hair<> Official UFO catcher style dolls use soft sheets of material similar to velvet (or velveteen) for the hair. For example, a character who has her long black hair up in a ponytail, with bangs in the front would have the back part of her head constructed of black velveteen, a small sheet of velveteen sewn in between the join of the top of the face and the top of the head (for the bangs), and a small sheet of velveteen would then be glued (or sewn) to the middle of her head for her "ponytail".
A character who has simple long blue hair would have the back of her head constructed with blue velveteen, with a long sheet of velveteen sewn in between the join of the "top head" to the "mid-head" pieces. A couple thin strips of blue velveteen might also be sewn in to the sides of her face.
You don't need to follow these "rules" of hair, but if you want to, you'll have to plan ahead and make your own templates for your hair.
A note on sewing
I prefer to do everything by hand. The pieces are so small and it's easier to be precise this way. I usually will use a machine on the body, but find myself manually turning the side-knob instead of using the pedal ^^; I guess you could also do this to assemble the head if you wanted… but I just do the whole thing by hand anyway.
Assembling the Head
Cut out all the head pieces (chin, face, top head, mid-head, bottom head, ear) with skin-colored flannel (*If you plan to use velveteen for the hair, cut out top head, mid-head, and bottom head pieces with velveteen instead of flannel). Note that you need 2 each of top head, mid-head, bottom-head, and ear (*ear pieces should be stiffened with fray check or clear nail polish. Do not add seam allowance to the ear pieces as the only sewing involved with the ear pieces is sewing them in between the face and head pieces along the dotted line shown in the template.)
First, sew the dart into the face piece.
Then, sew the chin piece to the bottom of the face piece.
Next, sew the sets of 2 (top head, mid-head, bottom head) together along the lines that indicate "center of head"
Next, sew these (now) 3 pieces from the previous step together. (*If you're using velveteen for hair, sew the sheet of hair-piece in between "top head" and "mid-head".)
Pin the finished back of head piece to the face piece (*if using ears, be sure to pin those in as well). The sides of the chin piece should also connect with the back of the head, and there should be an opening at the bottom of the entire head. I still have some issues with my chin-piece, so you might want to play around with it.
Sew the entire head together!
Turn right-side out and stuff tightly.
Assembling the body
Sew the two body pieces together, leaving the neck open.
Turn body inside-out and stuff tightly.
Sew the bottom-foot and side-foot pieces together (*if your character wears shoes, make these pieces of fabric the color you want the shoes to be)
Stuff the shoes/feet and tack them on to the bottoms of the legs.
Completing the basic doll
Tack finished head to finished body.
Draw eyes onto white fabric. (*the hole in the center of the template is where the pupil is supposed to be. For the tops and bottoms of the eyes, press the template to the fabric and draw lines just around the pointed side of the template with a black fabric pen. Remove the template and draw the rest of the eye free-hand with other fabric pens)
Once the eyes are drawn and dried, cut them out. (it's usually a good idea to draw the tops and bottoms of your eyes thicker than you want, so when you cut the eyes out, some of the eye you drew on will be cut away. This ensures there will be absolutely no white fabric left in the character's "eye-liner")
If using a closed mouth, test the black fabric pen on some extra skin-fabric. If that's okay, carefully draw the mouth on your finished doll. If not, draw a mouth on white material (or use black material) and cut it out like you do with the eyes.
If using an open mouth, cut out a pink piece of cloth in the desired shape and stiffen with fray check.
Once all the facial pieces are ready, glue onto the face with Elmer's glue.
Sew a loop of embroidery floss into the top of the head (UFO catcher dolls are traditionally hung from the ceiling or on the wall)
Clothes, accessories, etc.
I didn't bother to make patterns for these… Just experiment. (Again, I assume you all are advanced sewers). Remember that official UFO dolls do not have removable clothes, so it's okay to use glue or to sew clothes directly onto the body. Felt works very well for baubles and don't forget other wonderful things like pipe cleaners, fake fur, pompoms, feathers, etc.
I guess that's all you need to know. Anyone who's bought a pattern from me and has questions can email me with them and maybe I'll start a FAQ section.