What the noodle doin?
Alrighty! While I'm making progress on Helena and v10, in today's post I finally explain what exactly it is I'm doing when I'm working on my model. I've made this step-by-step outline, here we go!
The first step is deciding what the LoRa needs. It can be anything. Absolutely anything. A character I need to generate consistently, clothing, a location, a sex position, anything. I collect a huge amount of images whenever I think "hey that looks neat", but one thing I try to do is have each image pull double duty. An image of Bluebell would improve the AI's ability to generate her, and the model kinda sucks at 2koma comics, so let's do a 2-panel comic involving bluebell. And Yu too, why not.
In this case we'll just take some screenshots from an old dragon ball fighting game and slap them into a white border:

Next, we'll draw over it manually so we can inpaint it to look nice. The most important aspect at this stage is getting the general color outline, I cannot stress enough that this stage takes basically zero artistic skill:

Now we need a prompt. Here's what I wrote:
meme face, 2koma, head only, v-shaped eyebrows, white border, smirk, mouth closed, looking to the side, duo, leaning forward, outdoors, blue sky, animal crossing, trees, clouds, daytime,
1boy, cute boy, femboy, brown hair, short hair, t-shirt, red shirt, short-sleeved shirt,
sy-shop, animal crossing, furry female, shortstack, domestic cat, feline, blue fur, monotone body, dark paws, anthro, pricked ears, dark ears, light blue hair, hair tuft, thin eyebrows, red eyes, pink nose, grin, closed mouth, cleavage, red apron, medium breasts, sideboob, naked apron
All of this is covered in my img2img section in my stable diffusion guide, but basically I use part of the prompt, inpaint the top at varying settings until I think it looks nice, then inpaint the bottom the same way. Here's what it looks like when we're done inpainting:

Looks nice right? But unfortunately we now get to the painful part. Look closer.

Closer.

You see how blurry it is? Everything in our training data will influence the model, and this may look kinda blurry now, but if we train our model with blurry pictures the model will carry over that blurriness on top of its own natural blurriness. From there things will spiral out of control and we'll end up with slop. So, let's upscale it:

Much sharper! Except look closer:

Yeah, that's not ideal either. Thankfully we can use img2img to improve the quality of the lines. I have a multi-step process for all of my upscaled images to get them at the quality we need for training. First things first we'll be doing an img2img pass at denoising strength 0.3 on the NTRmix checkpoint. Here's the output:

Yep, it's nearly exactly the same. The changes are downright microscopic, but this stage is important because we'll need to manually polish the image every step of the way after this. This first pass is just to make the lineart slightly less bad without potentially breaking the image.
Alright, that was the last easy step out of the way. Next we'll be doing an img2img pass at denoising strength 0.5 on the NTRmix checkpoint:

And you can already see something's been screwed up, but there's often hundreds of smaller errors you won't notice at first too. So, I overlay the 0.3 with the 0.5 and go over every single inch in excruciating detail, erasing the areas of the 0.3 where the 0.5 looks better, ending up with a fusion of the two. This gives me the line sharpness and detail of the 0.5 without any of the AI jank:

We are now in the polishing stage. This is an extremely time-consuming process. I can lose hours of the day polishing up a handful of images.
I'll keep doing 0.5 ntrmix passes until I feel the image is just about perfect, at which point I need to make the image less shiny. Remember that small AI quirks go unnoticed, but when they start compounding they become a big problem. NTR mix has a habit of making skin and fur look very glossy, almost greasy. It also tends to give us low-saturation output. So we need to counteract that by doing yet another img2img pass, this time with another checkpoint. I use mistoon for this, as it's much less shiny and much more saturated. So, let's do a pass with mistoon and do the exact same thing as earlier. Overlay, erase, polish:

I also need to keep track of how far along each image is. Doing an 0.5 ntrmix pass before the 0.3 one will result in some blurry lines slipping through, and the mistoon pass must be done last. It can be helpful to keep different batches in different folders for this reason.
On top of all that, if I notice a major anatomy error at any stage, it can't easily be fixed. I need to reduce the size of the image and go aaaaaall the way back to the inpainting step, and do everything over again. And each polishing pass has the chance of some new anatomy error slipping through.
But we still aren't done. There's four major areas that are so important that I have to handle them manually at this stage. 3 of the usual suspects aren't issues with this image, thankfully. These are:
-1: Light outlines. Sometimes, right around the black outlines of our characters there will be a lighter outline where the color of the background meets the black of our outlines. Here's what this would look like if it were present in our image:

-2: Stray hairs. Small messy hairs will interfere with out ability to remove backgrounds, so I try to get rid of them. Here's an example:

-3: Bad hands. Self explanatory. Training your model with images with bad hands will, shocker, make your output images have bad hands too.
-4: Bad eyes. Finding a consistent eye style for the model is extremely important for quality. So, for every single image, I often just erase them and draw in new ones myself. Sometimes the eyes already look fine but I don't want to risk it. I'll also take this final opportunity to redraw anything else I feel looks a little jank, like sharpening the character outlines, teeth, hairline, fixing their eye direction, etc.

Note: you don't need it to look better than the AI, your final drawing can look a lot worse, but so long as it's your own weirdness and not AI weirdness, the final model will turn out better. A mistake in 1 out of 500 images won't have a noticable impact, but the AI doesn't make a mistake just once, it makes the same mistakes over and over, just in barely noticable ways.
After redrawing the eyes I then sharpen up the outline, etc. Whatever it takes to fix as much AI jank as I can find and finally, we are STILL not done. Because now the image needs to be retagged. For example we were making the image the 'femboy' tag was helping us get Yu's iconic look, but the final image doesn't look all that feminine. We need to go through and find every single tag that is no longer accurate and remove it. Then we need to go through the tag database and find everything missing, like 'areola slip'. On top of that, anything we don't want in our final model needs to be tagged or manually fixed. Skin still shiny? It must be tagged. Still some stray hairs? Tag it. And I'll remove any redundant tags like 't-shirt' when we already have 'short-sleeved shirt' too. Here's our cleaned-up taglist:
meme face, 2koma, upper body only, v-shaped eyebrows, white border, smirk, looking to the side, duo, leaning forward, outdoors, blue sky, animal crossing, trees, clouds, daytime,
1boy, cute boy, femboy, brown hair, short hair, red shirt, short-sleeved shirt,
sy-shop, animal crossing, furry female, shortstack, domestic cat, feline, blue fur, monotone body, dark paws, anthro, pricked ears, dark ears, light blue hair, hair tuft, thin eyebrows, red eyes, pink nose, grin, cleavage, areola slip, red apron, naked apron, sideboob
On top of that, when I have multiple different characters in one shot, I'll usually remove any tags that are core to their design and outfit. That makes group shots a lot easier in the long run. So for example bluebell should always have her natural hair color, so I don't need the 'light blue hair' tag.
Okay, we are finally done. One image down. Just...

A lot more to go.
And if you're wondering how long I've spent on the database as a whole, in my finished LoRa training collection, I currently have 1135 fully polished, cleaned, and retagged images. Now also keep in mind that I need to train the model, then test it thoroughly to find what's been mistagged, test if the training data is too shiny, not saturated enough, etc.
I'm sure this all sounds quite boring, but I actually find it very relaxing. I used to draw a lot, but for health reasons I can only draw in short bursts these days. I'm very grateful I have time to spend messing around with all this, thank you! And sorry for all the times I've fallen down the rabbit hole losing entire days to polishing images :P