I am certainly not some kind of expert on digital accessibility, but I spend a lot of time on Twitter and would like to think I have picked up a fair amount of information over the years about how to make sure my tweets can reach as many people as possible. There are fantastic disabled activists all over Twitter from whom I have learned these things, and although I can’t remember sources for each of the tips I am going to put below, credit definitely goes to disability Twitter in general for the fact that I know any of this stuff in the first place. (If you happen to know that certain tips below originated from a specific person or organization, please tell me so I can credit them!)
While I do often see these points made in tweet format, and try to retweet every time I see them, I do not know of a single consolidated document that compiles all of this into one place… so, here you go! In no particular order:
1. Caption your images! There are lots of guides out there on how to use the embedded image description feature – and cheers to Twitter for finally making that an option – but true best practice is to write an image description into the body of a tweet. This is because not everyone who needs image descriptions uses a screen reader that picks up the embedded information. Including a description in the tweet itself – or an additional threaded tweet, if there’s not enough room in the original – makes it accessible to more of your followers. Here’s an example of how to put in the body of a tweet:

Image description: screenshot of an April 19th Tweet from username “homo qui vixit awareness month @endeverstar” that reads “GOOD MORN FRENS / image: close up of black cat staring at camera” above said image.
I am not yet a a pro at the best way to phrase image descriptions, but this site gives some advice on that what information to include.
2. Provide line breaks when using the majority of any given tweet’s now-280 characters, to add sufficient blank space around your words. This helps some people with reading-related disabilities take in your content. For example (please excuse the random special interest TV show content, haha):

Image description: screenshot of an April 17th Tweet from username “homo qui vixit awareness month @endeverstar” that reads, “i like to think that the same way brennan is really good at the other-cultures’ social skills that she was able to learn explicitly through anthropology, [line break] she is actually really good at recognizing people’s faces because she was able to learn explicitly through anthropology”
3. Capitalize each word in longer hashtags so that screen readers are more likely to parse it out correctly rather than pronouncing it all as a jumble or acronym. For example, write “#ActuallyAutistic” instead of “#actuallyautistic”.
4. When you want to retweet something made up of an arrangement of punctuation or emoji that form a larger image, quote tweet it with a description of the overall content – otherwise it probably won’t make sense to people using screenreaders. Think bunnies-holding-signs, as in the below screenshot:

Image description: a December 12, 2018 tweet with username and logo blacked out for privacy. The main tweet content says “Bunny holding up a sign that says please be inclusive of aces and aros” while the quoted tweet, also with username blacked out, displays the sign described.
5. Either don’t post starkly flashing/flickering gifs and videos or make them easily avoidable by giving an epilepsy warning. This can help your followers with seizure disorders.
6. Either don’t post videos/audio that have sudden very loud sounds or make them easily avoidable by giving a warning. This can help your followers with sensory processing issues and/or PTSD.
7. Use emoji thoughtfully. Overuse (such as including more than a couple in your display name) can get really annoying for people using screen readers, and some autistic/similarly neurodivergent people have difficulty understanding/remembering the meaning or subtext that various face emoji have come to represent. For example, I know very little about the implications of the following range of happy-ish faces.

Image description: a line of 21 yellow face emoji, each a different expression.
If you do use these emoji, evaluate whether the meaning of your content is dependent upon them – can you add the intent in text too so that more of us will understand?
8. For cognitive accessibility, think about how you’re expressing your thoughts. Decreasing the amount you use acronyms, unexplained jargon, and idioms can help those of us with intellectual and/or developmental disabilities understand what you’re trying to convey. We also might not easily pick up on sarcasm, so putting “(sarcasm)” or “/s” at the end of a tweet can make it easier for us to understand your meaning.
9. Give content warnings for common triggers! This helps trauma survivors as well as some other disabled people prepare for and/or avoid topics that could prompt flashbacks or other harmful symptoms. This is not a trivial matter of trying to make everyone perfectly comfortable, it’s truly an accessibility concern that deserves your attention. Any given disabled person’s triggers might be so specific that we can’t warn for all of them, but I hope you’ll consider trying to remember to give warnings for some of the most common triggers listed below:
Abuse/assault
Death
Dental
Eating disorder triggers (including specific weights/BMIs/clothing sizes/calorie counts)
Eugenics
Filicide
Fire
Gore
Holocaust/Nazis
Institutionalization
Medical trauma
Oppressions, including everything from hate crimes to oppressive language (such as slurs and derogatory use of identity descriptors)
Self harm
Substance use
Suicide
…that’s a lot of stuff! So now is a good time to discuss: we probably can’t make our Twitter feeds perfectly accessible at all times, especially if we have neurodivergences that impact our abilities. This goes for content warnings plus every other recommendation I make in this post. But in my opinion, that shouldn’t be a reason to just not even TRY to do our best. I know very well that I for one do not always follow these recommendations, whether out of completely forgetting or out of lack of spoons or time constraints or et cetera. But it’s a disability justice issue, and I hope everyone will consider giving their best effort to it. Your disabled followers deserve to engage with your content as much as your abled followers do, and I hope you’ll try to do whatever you can to make that possible.
So, how do you format content warnings? This is a common structure:
“CW [list topics]///
[a couple of line breaks]
[content]”
“TW” (trigger warning) and “CN” (content note) are interchangeable with “CW”.
You might have a follower at some point ask if you can add content warnings for uncommon triggers specific to their own disabilities. In my experience the most helpful way to respond is to take your best honest guess about whether you’ll remember, and assure the person that you won’t hold it against them if you fail and they unfollow (or if they want to unfollow immediately based on your estimate of whether you’ll be able to warn adequately for them).
10. When you link to outside content such as articles or YouTube videos, include information about accessibility in the tweet so that disabled people know whether it’s even worth clicking. Tell your followers whether there are captions on videos and transcripts for podcasts, give content warnings for subjects handled in the linked content, et cetera.
Okay, those are my top tips – do you have more? Please comment below, I’d love to hear about them!