This is a description of communication strategies which have been helpful to me  in social situations where I was confused. It is relatively unedited; some of the content may be obvious and banal, or redundant. 

[Edited to move out of footnote, thanks Aorou] I am autistic, and often have had difficulty with communication. These are some things these strategies have helped me with: 

-difficulty distinguishing tone of conversations, difficulty speaking in a particular tone or matching the tone of a conversation

- feeling afraid to "say the wrong thing"

-speaking in more literal terms than most people, interpreting statements more literally than they were intended

-feeling like people are engaged in a social game that I don't understand

- and other difficulties in the genre of these listed

Hopefully this post will be helpful to someone with similar difficulties; it would have been helpful to me if I had seen it several years ago. 

[End of edit]

strategies / useful framings

1. If the literal content seems not to make sense, often the subtext or mood is the point.
   1. One time I was talking to two people and they both kept pointing to their things and saying in an exaggerated angry tone "ugh, this [object] sucks, it's so [adjective]". I thought that they were trying to request to borrow my things, so I offered. But they declined, looking confused, and one said "no, that's ok, I'm just in a bad mood today." I then realized that the point of what they were saying before was to communicate their mood, not anything to do with the objects they were referencing. The subtext of "this [object] sucks" was "I am in a mood where this minor inconvenience bothers me."
2. Pay attention to other people's responses to a statement.
   1. if I had noticed that neither person was treating the other's complaints as serious, this would have led me to consider what else they might be trying to communicate indirectly.
3. Many times, when I am confused by a conversation, I find it useful to think of people as communicating by acting out roles that are interesting/useful/funny/etc, rather than communicating directly.^[1]
   1. In the example above, I said that the subtext of "this [object] sucks" was "I am in a mood where this minor inconvenience bothers me." But I don't actually think either of the people were annoyed in a way that made those specific inconveniences important to them. Instead, they were each playing the role of someone who was really annoyed at these inconveniences. 
      1. What they were really communicating to me / each other was the subtext of the fact that they were deciding to play that role, which is much more ambiguous. It could be "I'm bored and want something to do" or "I dislike the person/process that gave me these objects and am compelled to complain about their decisions" or "I'm in a bad mood and want to express it to people without being too serious or specific." (that last thing is what I think it was in this case.) 
   2. The safest response to someone who is communicating this way is to play along with the role they seem to be acting out and wait for more information to clarify their intent. 
   3. Most people are not consciously trying to act out a role. It's just that the unconscious combination of exaggeration, sarcasm, and communication through subtext often amounts to doing so.^[2]
4. Respond ambiguously; let the other person clarify what they mean through further conversation 
   1. the more possible interpretations of the conversation a response works with, the safer the response is to say
   2. often, the ambiguity was deliberate and is a way of gauging the other person's mood/opinion/response to decide what next to say. it is not necessarily expected that the nature of the conversation is known yet
5. Fall back on safe, simple, nice things to say.
   1. making long comments, jokes making fun of the person, and negative comments about others are all a bad idea when uncertain or confused about the conversation
   2. assume good intent on the part of the speaker when confused
6. if tone is important^[3] it may be easier to work backwards from tone, not forwards from content.
   1. there is usually a way to, given a tone, find words to describe a concept. there may not be a way to, given a wording, say the concept with the desired tone.
   2. Example: It is not so hard to express the concept of a request not to do X in a gentle tone: "please do not do X" ,"I wish you would not do X", "It bothers me when you do X because Y" , and many more. It is highly difficult to say "I hate how you keep doing X" in a gentle tone once that wording has been decided. 

My mental process when dealing with a confusing social situation

1. First priority: stall, wait for more information
   1. try to respond in the same character as what they said
   2. ideally, respond in a way that preserves the ambiguity 
      1. for example, if they said "I'm so sad" in an ambiguously sarcastic way, saying "aww, why" with a slightly exaggerated concerned tone works whether the statement is serious or sarcastic. Saying "I'm always here to talk" may be falsely assuming they are serious. Laughing may be falsely assuming they are sarcastic. 
2. Second priority: attempt to characterize the role they are playing and the possible roles you could occupy in response
   1. the complement to the role of "person expressing sadness" is "concerned friend."
   2. being able to predict what they will say next and knowing roughly what sort of replies are expected will buy more time to figure out what they are actually trying to communicate 
3. Third priority: attempt to determine the reason for the communication
   1. pay attention to prior context, other people's responses, facial expession, level of exaggeration, etc.
   2. they could be completely serious, completely sarcastic, using sarcasm/exaggeration to cover a real serious discussion, just bored and saying whatever, signaling endorsement/disapproval of a person/thing regardless of the truth of the actual words said, signaling only through the character/vibe of the role they are playing, joking, testing your response...
4. Fourth priority: attempt to do any steering of the conversation / non-passive input / humor
   1. Now it may it make sense to offer advice, say anything serious, say anything personal, communicate anything complicated, make a joke, or attempt to select a response to communicate something through vibes/subtext
   2. Because intent is clear, it becomes possible to stop the ambiguous role-playing by addressing the point of the communication more directly
      1. if it's pretty certain that "I'm so sad" was serious, "I'm always here to talk" becomes a possible response
      2. if it's pretty certain that "I'm so sad" was sarcastic, laughter becomes a possible response
5. ff it still doesn't make sense, asking is usually fine
   1. "are you being sarcastic" / "what do you mean" / make a confused face / etc
6. of course, all of these have to happen in time with the conversation, and will be more like wordless intuition-concepts than well-thought-out analyses

Examples

bold=other person, regular=me

the "thoughts in the moment" are mostly cached responses or split-second decisions

the "analysis" is more developed explanation of interpretation so far

Example 1: 

This conversation is interesting because it manages to acknowledge and overcome the awkwardness and potential for conflict surrounding the difference in scores, almost entirely by communicating through subtext. It would make me a little nervous that something was misunderstood, and if it seemed to still be a source of tension later I wouldn't want to keep communicating in subtext, I would address the issue more directly. 

Example 2

Example 3

This one is a true story  

Example 4

1. ^{^}

   Even though it seemed less effective and more confusing at first, and is far from being easy or automatic even now, communicating this way has advantages. 

   - it can be fun, humorous and casual

   - ambiguity is easier, which makes communication less high-stakes

   - it is easier to "test the waters" of what types of interaction the other person would be open to, without saying explicitly that this is what you are doing

   - it makes it easier to share vulnerable thoughts or emotions in a plausibly-deniable way, and with less awkwardness

2. ^{^}

   There are some people who, it seems to me, act approximately always as if they were playing a role, even in their own thoughts. The habits of communication through subtext are so deeply ingrained for them that they even think in subtext. The act of communication seems to be, for some people, fundamentally a matter of embodying precisely the right situational vibe, not using the most descriptive words. These are the people I find most difficult to communicate with, although they seem to have no trouble communicating with each other.

3. ^{^}

   some times when tone can be especially important

   - when sharing vulnerable emotions, so as not to scare each other off

   - when criticizing someone, so as to avoid the common misunderstanding where the criticism is taken as evidence of character judgement

   - when trying to avoid another common misunderstanding: apology vs defensiveness, suggestion vs criticism, request vs demand, etc.

   - when talking to people with power over you or that you have power over, for obvious reasons

   - when trying to offer comfort, because it might not work if the tone is wrong 

4. ^{^}

   a cliché, but apologies really work so much better when you do this