Putting together a BJD is a tricky task even for the experienced hobbyist, not to mention novices. If you buy a Forest Dweller which has a standard custom work done you could just enjoy a tiny animal as is. But if you plan to buy a human doll or head from me, you have to order the faceup from me or paint the face by yourself, to choose a proper body in case of hybridization, to pick the right wig, eyes and clothes. This info will help you.
I sculpt my molds in a way they could fit on a several bodies of other BJD manufacturers. Some people would like a lean character, others may want more broad and muscular one, so choosing a certain body would help to create the character you want. Every mold has the info on suitable bodies, and as customers provide hybrid photos I add them to the page.
I provide matching bodies for my female head molds. Making male bodies is in plans.
My animal dolls can wear a simple glass or acrylic BJD eyes, required diameter is listed on the page of each doll.
My head molds take 8 mm eyes: they provide the most realistic look. The best eyes that are both great looking and affordable are Pabol oval glass eyes, that are sold by several dealers, such as Kemper Dolls or Blueberry Style.
It's much easier to choose a wig for females than for males. I'm often asked where I've got those short wigs for my male dolls. I made them by myself, and you may try my tutorials if you wish:
Meanwhile look at those sites which have a plenty of wigs:
Luts - nice wigs, some are short,
Dollmore - the same,
Alice's Collections - the same,
Monique - lots of epic female wigs. Their photos don't do them justice.
You can buy a short wig for your male doll and cut it even shorter.
While choosing a wig please pay attention to the size: it's mostly specified in inches.
I offer faceups for my own molds, as an option.
If you prefer other artist to do faceup, I don't take it personally, and even feature these faceups on my social media, because it's a joy to see how other artists envision my molds. I'm also very happy if the customer decided to paint a doll by themselves. That's what BJD doll is for: to be a field of artistic expression! I love variety and different approaches.
A lot of faceup artists offer their services, but the best artists are often busy, and their services cost a lot. So the first thing you need to figure out is how much you are ready to spend on the faceup. The second important thing is a desired style: an artist who tends to paint a sweet lolita girls with feathery eyebrows and glamourous boys with glossy lips most likely wouldn't paint a brutal character with a beard. Begin your research having that in mind.
What fits a certain body highly depends on what body you choose for your head. Some bodies have a lot of clothes and shoes to fit on, other ones have less. Usually the company which sells bodies has some clothes in stock, but not always. I do only custom clothes for my dolls, they're mostly OOAK.
The general rule is to know the measurements of your doll body and to research the market: you can buy clothes that fit the bodies of a similar size. Usually 1-2 cm is not a problem. If you like a precise fit, then your option is to sew or commission though. I never bought nor clothes neither shoes for my dolls, as I make everything by myself, and was obsessed with a proper fitting, but when I was able to dress 70 cm high FaCo Doll body into the clothes and shoes made for 65 cm high Soom Supergem body I became much less skeptical about fitting.
You also can ask owners of the same bodies where they shop for BJD clothes: many people willingly share this info.