I tend to invest more of my time into studying and using fake languages than I do making them. Here are some of the things I’d like to see when a new language bursts on the scene. Keep in mind that I’m writing from a fan’s standpoint in a field where people generally write conlangs to scratch some idiosyncratic itch and aren’t really interesting in getting any fans. I’ll also address auxlangs a bit as well, where users normally are actively sought.
Basics. Let me know if this is actually a language. Shyriiwook, the language of Chewbacca in Star Wars is a sound effect, not a language. The few attempts to create a wordlist or description are incomplete enough that no one could translate a text or do any other task in Shyriiwook if they had to. This contrasts with relatively complete conlangs where you can say a lot.
Goals. I want to know what the goals of the language were and especially if you failed to achieve your goals, tell me what the language turned out to be good for. E.g. toki pona was intended to be somehow Daoist, in practice it turned out to be a nice toy language for doing linguistic experiments that would be too time consuming with a real languages, i.e. creating a semantic web for the entire lexicon.
The creator vs the fans. Auxlang creators tend to at least be a clear that they hope to have a fan or two. Conlang creators, especially if they have created a “big-culture” conlang need to make it clear if they want fans and what they want the fans to do, keeping in mind that these are unenforceable gentleman agreements amongst strangers. If I had freetime, I would create an english re-lex of Dritok, because the phonetics are more interesting than any other part of the language. If I had free time, I would learn Kēlen and see what an human, East coast USA version of it might look like. I have no idea how the creators would react, it would be nice if newly published languages outlined how they would like people to interact. It seems premature, esp if you don’t have fans yet, but I believe that people will participate when the path is clear. When the path isn’t clear, they will keep quiet and not participate. (I pick Dritok and Kēlen because as far as I know, their creators seem to be nice people who probably would tolerate this sort of participation) From reading Arika Okrent’s book, I’m sure there are other conlang designers who feel that the only permissible participation of fans is a that of passive adoration. And a license. What is your license for your conlang.
Audio. Boatloads of fake languages appear to be pure phonetic plays, i.e. the main developed part is the phonetics. Please show it off with audio and video with subtitles and transcripts.
Gloss. If the syntax is interesting, I care about the gloss. I generally don’t even try to read the foreign text. One line of gibberish looks like the next line of gibberish to me. But the gloss is interesting. Use standard glossing abbreviations unless you have a truely novel grammatical thing going on. Provide a variety of examples to remind people how an abbreviated part works. As an amateur, I’d much rather see a marginal example from English than a dead on example from a rare language– for example, if you are reminding your readers about how evidentials work, then show an example like, “According to Joe, the crime happened at 6AM”, even though a better, but less understandable, example might be from a language with obligatory evidential morphemes.
Poster Ready Art. If the script is the main attraction, give me something I can print out, or instructions on how to use the script. If the script really is a pure script play, then please make sure that there is a way to write English.
Lessons. I’d like lessons to start with the most developed part of your language. If you have some ideas concerning tense, then that should be lesson one. Too many fake languages start out with the Phonetics, Morphology, Syntax, Discourse outline and never get pasted the first or second section. Also, the lessons should restrict themselves from examples drawing from not more than 500 to 1000 words, preferably 200. Also, twitter lessons are a good idea. Take your lessons and split them up into 150 character chunks and broadcast a few a day for a year.
Flashcards. Anyone who is seriously studying foreign languages is using spaced repetition flash cards, such as ANKI. Gimmie my vocab in ANKI format and don’t make me have to do the extra work of creating a deck.
A Forum. I don’t mean only a phpBB forum, but just any suitable online location for fans to communicate, be it a mailing list or a twitter account.
Auxlangs. I see auxlangs as one of many possible recipes for creating a fake language. They have a goal of being used by more than one person, sometimes they have goals of competing with global lingua francas. Global lingua francas are valuable because of the massive network effects: the more people in the network of French or English communication, the more valuable French or English is, no small language, be it a small endangered heritage language, conlang or new auxlan can initially be expected to compete. An auxlang needs to provide some benefits to people right away, long before there is a critical mass of users. Focus on those benefits first when marketing. For example, the main benefit of Esperanto for the conlang geek is the opportunity to pick of chicks at the next Esperanto conference.