Customizing Blythe dolls (help)

3 and 4 are the same as for bjds, check out the customizing threads on here. Pastels, msc or other sealant, watercolor pencils or paint- acrylic or watercolor.
Cant help you with 1 and 2, though, but i do know a lot of blythe artists use exacto knives

 

You can use the same tools for carving that you would use on any other type of hard plastic including resin, as the heads appear to be made out of either ABS or PVC. So, you can use the same kind of sandpaper and power tools you would use for resin. I don't own a Blythe (yet!), but I have carved, sanded and modified a lot of OT action figures and dolls, made out of those materials and they pretty much work similarly -- resin is a bit easier to mod if only using sandpaper or you don't own a power tool, but you can certainly use the same tools and sandpaper grades for the same purpose (coarser for modifying, finer for smoothing, finishing/polishing). The body appears to be vinyl (I haven't found a reliable source that actually lists what the doll is made out of), so that would be harder to mod, if you want to also modify the body. Most people assume PVC is the same as vinyl and call most fashion dolls vinyl dolls for that reason, but they are different types of plastic (pvc is polyvinyl, but it's not the same type of plastic as vinyl and won't sand/carve the same). Vinyl is a pain to work with (IMHO), even if it's the harder type as opposed to the squishy kind, although the harder type of vinyl is a bit more generous when sanding/carving.

As for what media is best for eyebrows, that depends on your skills when it comes to painting. I love painting with acrylics since I was a young child, and I refuse to use pencils for face ups, simply because I am a weirdo (I get the nails on chalkboard feeling, when I draw with pencil on a 3D object). I feel acrylic paints are easy to work with, the only issue I have is my shaky hands, but that's a "me" problem. You can use pretty much any art material you can use on resin, and as the above commenter suggested, it would be a good idea to look at the customization sub-forum on here, but just avoid oil-based media because it will permanently stain any and all kinds of plastic. Hope that helps, and good luck! (:

 

Painting Blythe, as others mentioned, is pretty much the same as BJDs. So just look for a BJD painting tutorial (the FAQ has a couple linked: /threads/the-big-bjd-faq-guide-for-newcomers.850259/).

For carving, Coolcat has some useful tools: ☆ Cool Cat Collection Shop． Doll Accessories ☆ -- Custom Tools
They have some other things for Blythe customization too (eye chips, replacement parts etc). Some customizers, once they are more skillful, use a dremel as well. It's just a lot faster, carving a Blythe takes forever by hand, but also less forgiving!

What is more complicated, is taking apart and putting together your Blythe. Not all Blythe are created equal. Depending on the face mold (for example EBL, SBL, RBL etc.), it works a little differently once it comes to removing the hair/dome inside. Taking out the eyemech is a pest. And overall, you just need to be a bit more rough with them versus a BJD. I have quite a couple of them, and I still feel stressed when I crack apart those face halves
Make sure to check some tutorials before opening it up, and put all the screws and little parts into a bag so you won't lose them.

 

Definitely look at some online tutorials for taking the head apart and putting it back together so you can get the eye mechanism springs done right. I left one undone so I can manually close my girl's eyes. I use sturdy woven ribbons for her strings.

If you're going to change eye chips look up the different methods to see which you prefer. I heated mine in hot water which helped to soften the white part. It's not as complicated as it sounds but it does take some patience. Getting the mech in and out of the head was more troublesome for me.

As for the face I was okay with her general look, I just painted over some of it with acrylic paint and she's lasted so far. Didn't feel the need to break out the power tools.

If you're going to Cool Cat take your time to look around. The Blythe carrying cases will fit many Yo-SD and off topic 1/6 scale dolls. I was lucky enough to match the fabric in mine and made some other bags to go with it. They even sent me some free DIY eye chips with an order.

 

Oh, and if you reroot you can get soft head domes. BUT you have to know what kind of Blythe it is in the alphabet soup to get the right shape.

 

I'd recommend bebeblythe on YouTube, they have alot of very good videos on customizing and repairing blythe dolls, even have a newbie series for all the basics that more experienced collectors might forget about