Hii!!! It's been a little bit since I've been on here. I'm in the beginning stages, still learning about BJDs. The thing I'm most unsure about right now is sizing. I plan to order the eyes, hair and clothes instead of making them myself and I want to make sure they'll fit properly. If anyone has any links to places that describe the sizes in depth, for example what size eyes to buy for what size doll, that would be spectacular. I have very limited knowledge about this area currently. Any help is very much appreciated.
Look at different doll companies web shops. Often they list the dolls measurements and recommended wig- and eye size. Look at several different dolls in the size range you are interested in. That should give you a general idea on sizes. Sometimes, however, size is a matter of taste. Eyes for example can often be changed for a smaller size than the recommended, if you prefer a smaller iris and to see more of the white surrounding it. On some dolls that work fine, on others there may be a slight gap at the corners. You will never know for sure until you've tried it. A thing like eye size can vary a lot with different sculpts, even in the same size range. Depending on how realistic or stylized the doll is. On the same note, eyes in the same size range may differ a lot in shape and how big the iris is, depending on eye type, material and so on. I hope that helps and that I didn't just add to your confusion.
Those are things you can figure out once your doll is complete or near-complete. You can figure out what wig size by measuring your doll's head. Figure out what eye size by measuring how big your doll's eyewells are... Same with clothes - measure the body, compare to measurements of doll clothes to see what will fit. You can, of course, look at an existing doll or doll line to see what their measurements are, and make yours similarly, if you'd like your doll to be easier to outfit (dolls with strange proportions like super wide stylized hips and a tiny waist, for example, you're gonna have a near-impossible time finding premade clothes to fit that). Check out some company doll sites and look at their measurements. I know Fairyland has this great chart of sizing for all their dolls, and they have a wide range from big to super-tiny. It doesn't show the eye size but you can see the "recommended" eye size for each doll if you go to their individual product pages. Should give you a starting point - and I know other manufacturers have similar info available, not just Fairyland.
If you're wanting to figure out what size to make your doll, I know Den of Angels has a database of different doll sizes, including head sizes, hip sizes, etc which can be useful for you if you want your doll to fit a specific clothing size, or eye size. Something you could look into would be certain doll eye sites, they give you information as to whether an eyeball is "low dome" or high dome" (a high dome eye would mean a deeper eyewell, for example, or a rounder eye might require a rounder eyewell). I've been looking into this as well, and I think what I'm probably going to do is buy some cheap eyes that fit a doll of the size of the guy I'm going to create (he's likely 45 cm or so), to see how they look in his eyewells. From searching on DOA and other places I know that 45cm tends to take 10-12 cm eyes quite well, but it depends on the size of your doll, I know there are a number of forums that address what size of eye/wig to go with certain sizes of doll. I tend to make my own wigs but if you wanted to buy a reasonable one just to try it out that might be a good idea--ebay can be pretty good for cheap wigs that work as good trial pieces, and the sellers often provide helpful measuring charts so you can often just measure the circumference of your dolls head and go from there. Hope that helps a little A couple of eye sites to check out for good sizing/description info would be Safrindoll (they have a large selection) or Etsy (specifically, KNIK Lampwork, but there's other eye sellers there as well). Best of luck