Keep in mind these are just my personal thoughts on adoptables and not a be-all end-all guide. I'm not an artist myself, and everyone feels differently about the best way to make, sell, and purchase adoptables.

1. Adoptables are fine as a supplement to your other work. I generally prefer to see adopts done in batches of three to eight, with a bit of time between them for the artist to draw other original pieces. I get bored and unfollow artists who post only advertisements for their adoptables.

2. It depends upon the level of original work involved, but I usually just see front views unless the back has a sufficiently complicated pattern to warrant it. Reference sheet style front and back images can be common in adoptables, but when they are they're usually done from a template the artist creates in advance so they can reuse their line art—that way the only "original" work being done is applying colors to speed up production. If original line work is being for adoptables, it's usually just a front view in a relaxed pose.

3. In my experience, species is less important than interesting fur/skin patterns. Just don't go ridiculously intricate—a pattern can be "complex" like spots or stripes without being "intricate" like tattoos.

• If you're doing plain/ordinary fur patterns, with clothes. If you're doing complex/unique fur patterns, nude. If you're doing complicated or distracting clothes, draw them on a separate layer and offer the nude version as a bonus to the buyer. I would keep nude versions SFW unless you're specifically trying to sell fetish characters, purchasers can always ask for NSFW versions if they want.

• Front view only if completely original work, if it's a "standard" fur pattern, or if it's a pattern that can be extrapolated from the front view (ie: leopard print on the sides indicates leopard print on the back). Front and back only if the back view is necessary due to a complex fur pattern.

• Keep your lines simple but get creative on colors and patterns. Adoptables should be unique, and what makes most characters unique is their fur pattern and hair. I usually see adoptables going for $25-50, often closer to the lower end, which reflects the mass-produced or otherwise low-effort nature of them. Creating them in large batches from templates also helps to mitigate the time cost if a few of them don't sell.

• I'd check how demand is before offering complementary anything. Remember that your adoptables not selling might not be a matter of people thinking they're not a good value, potential buyers might just not be seeing them in the first place. A better option might be offering a portrait or other commission as an add-on, possibly at a slight discount to your usual rate for such a piece to make it feel more like a bonus.

Final thoughts:

As a general rule of thumb, if you're doing a relatively simple fur pattern or otherwise normal-looking character it's better to do an original art so the buyer doesn't feel like they are just buying generic from a puppy mill. If you're doing a complex fur pattern it's better to color from a template, the uniqueness of the pattern makes up for the reused lineart.

Don't shade your adoptables. Shading is extra work that doesn't add anything unique to the character, and makes it more difficult for other artists if the piece is used as reference to commission more art down the line—which it usually will be!

Advertise on multiple platforms, especially social media where you can get friends to reblog to their own audiences for additional visibility. A tweet can reach a very large audience because of the ease with which someone can share it with everyone they know; a single click makes the image show up on all of their followers' feeds (another reason to keep adoptables SFW). A FA post can only be shared to people willing to click a link, and if those people aren't already an FA member then being blocked from viewing it by mandatory site registration may be too much effort just to see what it looks like.

Example adoptables:
http://www.furaffinity.net/view/22610069/ A typical husky and a leopard-print griffon, original artwork, simple clothes, front view only. Note the wings on the gryphon were requested by the buyer, who paid an additional fee for them; the original version did not have wings. $25 each plus add-ons.

https://pixel-prism.deviantart.com/.....TION-683639309 Unicorns and griffons made from templates drawn by the artist specifically for this batch, nude, front view only. Note that even though the heads and bodies are made from a template, the hair and tails are unique; the fur patterns are complex, but not so intricate that a back view is necessary. Auctioned starting at $20

https://pixel-prism.deviantart.com/.....opts-699532877 Multiple species, original artwork, complex clothes with nudes included as a bonus, front view only. The artist was in a mood to draw lolita fashion, and decided to use it as an excuse to make themed adoptables. More effort than is typical for adoptables. Auctioned starting at $20, bonus, free portrait if bids hit $100, free reference sheet at $200 autobuy.

http://www.furaffinity.net/view/20739629/ "Egg" adoptables, a unique variety of adoptable where the artist has only revealed color palettes and either has not started the artwork yet or is making buyers purchase them semi-blind. The buyer may have limited input on the final result if work has not yet been started. This particular artist allows buyers to choose the species, the build, five key words, and which color from the palette they wish to be the primary. $30 each plus add-ons. The results from this egg auction are here:
• http://www.furaffinity.net/view/21398800/
• http://www.furaffinity.net/view/21398604/
• http://www.furaffinity.net/view/21398653/
• http://www.furaffinity.net/view/21398685/

thanks allot for your input, there's allot of stuff to take in, i'm not planing on only doing adoptables tho, ever if it were the case, i'd make them sufficiently different from one another.

Thanks for the shutout on twitter too, greatly appreciated, i'll have to start up on social media too, not good with managing all these accounts.