When I bake my texture in blender it becomes cloudy

If you're using an already existing texture, you can shrink the texture and UVs down, and place it in the accessory area you're using (map here --> sims4studio.com/thread/62/fix-uv-map-template in second post). 

Transparent parts of accessories tend to turn skintone-colored or tinged with whatever color the base color is (just so you're warned), so you won't see the actual result until you're ingame.

As for adding more colors, you can add as many extra swatches as you want in S4S, so the red wine is easy enough to add (just make a second texture and add it as a second swatch). 



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(Now that I think about it, I may have skipped some parts in the whole accessorymaking process, or maybe it's not needed or something, because so far I haven't done quite a lot of the things that seem to be necesssary for hairs or clothes when I've made accessories, and haven't had any problems with that (the second UVmap thing, painting weights green, etc.).  Might have done some of them in a slightly roundabout way, though... But then again, the tutorials are a bit all over the place)

I forgot to mention - For the transparency problem, I've used glasses as a base, and used the glass part for the transparent bits and pieces. I think it's possible to add a transparent part to accessories, but this is a bit easier. If you don't have any non-transparent parts in the accessory you're making (but you still need the group for the accessory to properly export to S4S), you can remove everything except one face/polygon of the frames and hide it inside the head.

S4S doesn't show transparency for CAS items properly, so textures tend to show skin-colored or in the underlaying color used, but should show transparent in CAS and ingame.

If you bake the shadow overlay textures over a fully white textured item rather than one already colored you have some more options in regards to adjustments and coloring/texturing later. The fully white texture can be used as an overlay over different colors, patterns, etc., and can also be adjusted in a 2D program like Photoshop/Gimp. 
(Personally I tend to prefer UVmapping and then doing all the texturing and shadow overlays in Photoshop, as it doesn't limit you to just what Blender allows for. I'm also not too fond of the overlays Blender makes - I think they tend to be either too strong or too cartoonish, depending on how they're applied, among other things. I'm  also still learning Blender, and haven't quite gotten the hang of baking textures yet, so maybe someone else can explain a bit more about that?) 

No, use just accessory glasses as a base (these have two groups, one transparent group for the glass and one solid group for the frame). I don't think there are other accessories with transparent parts.

You can recategorize the accessory wineglass later (remember to UVmap them as whatever you plan to recategorize them as, in case you want your sims to be able to use glasses - TS4 accessories don't allow for stacking unless the UVs are separate, or you get textures overlapping). 

I've only made accessory conversions from other games, which is pretty much the same as converting an object from ingame into an accessory,s o I think the method could work for you too.

This is roughly what I've done (and I've probably skipped a lot of steps tutorials say you should do, but it's worked for me so far - but I don't think I'll do a full tutorial, because then there will probably be a bunch of people telling me what I'm doing wrong... ). This is explained very 'quick and dirty' so it's not really meant as a step by step, either. 

1: Extract mesh and textures you want to convert, extract UVmap from mesh, and fit this in somewhere in the accessory map. Should be resized to one of these sizes vertically/horizontally, depending on what fits, best done with an auto-resizer like one found in a 2D program like Photoshop/Gimp/Etc. because most of the squares in the map are these sizes anyway (32, 64, 128, 256, 512, 1024). I tend to put the UV and texture together, resize, then move both layers into the map together, hide the accessory map, and then save one version of the texture with the UVmap (for the remapping) and one without (for the texture).
2: Figure out which accessory file works best for project (placement, age, etc.), make new file, extract mesh and texture.
3: Import the mesh (Append, or Import if it's an OBJ). Don't worry about textures.
4: Open Blender object, open UV view, import the texture with the new UVmap into the UV view, make sure the mesh you want to remap is highlighted and marked (all of it), mark the UVs, then scale down to fit the UVs.
5: Match cut numbers to the meshes you're replacing. Remove the ones you don't need (you need the same number the mesh file started out with!)
6: Save and import to Blender. (this is a "cheaty" way of linking the rig, by the way - not sure if it works for clothes, but it works fine for accessories)
7: Import texture to Blender. Save file.
8: Export from Blender.
9: Open file. It's now connected to the rig but not properly weighted.
10: Select/mark entire accessory (highlight vertices in orange), go to "Object Data" (looks like a triangle), set the vertex group to "b__R_Hand__" (or whichever joints fit the accessory) and assign.
11: Save file, import to Blender. 

The cut numbers under "scene" (under "S4Studio CAS tools" if it's hidden, I think?). For accessories these tend to be 0000 or 0001 depending on group. The cut number decides which item is replaced with what (names don't matter, you don't need to fix the names - S4S and Blender does this for you after reimporting).

If there are two groups, make sure the group you want to be transparent get the number of the original transparent group. 

Like I said somewhere above, you need to end up with the same amount of groups the file you exported from Blender has (glasses have two, one for frame and one for glass). 

If you intended for the wine to be a separate (and non-transparent) group, use the Frame group for the wine.

HOWEVER

If you just need one group, you need to still keep the other group but delete everything except one polygon/face, snap the vertices together, and hide it inside the head (weight it to the head if you want to be sure it doesn't pop out - I've had the occasional one of those). 

I think if you fix this, the frames will go away. 

(I've seen this trick used for TS4, but it's also a trick I've used in all my years of making TS2 accessories for hiding the lens, and as it turns out is a totally unnecessary step. There's probably something that can be done about both problems in TS4 too - both the issue of only adding the amount of groups you need, and adding transparency to that group  )

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I'm not sure why you got a black glass, but it seems to have been fixed somehow? Could be you forgot to change the texture? 

I also see you've UVmapped the glass in the hat area, so be aware that if you use hats (or other accessories mapped in the hat area) on a sim at the same time, you'll most likely get overlaying colors on the wineglass. 

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The package file isn't in the Google Drive file, so I can't figure out if there's anything wrong there. 

Did you by any chance use the "make empty" button on the other maps? You're not supposed to do that. If you want them "empty" you need them "neutral" instead. I got mine from the last link here: kouukie.com/objtoaccmasterlists4 "Blank specs, normals & shadows"

Replace those three, and it could be that helps on the textures.

You may also want to add a custom thumbnail (both female and male if it's for both genders), or you could have troubles finding it ingame. 


And right now there's two glass meshes in the mesh file if you export it from Blender. Probably because S4S is reading the import wrong. That's probably going to fix itself if you do the one-poly-hide-in-head trick, though. 


The glass does show with the skin just like I said it would (if you're worrying about the weird texture), but should show with the transparent texture ingame if you fix the double mesh (but looks like you figured this out).