Hashtag writing prompts on Twitter are great fun and a good way to find other authors. I know I'll like their work, because I've already seen lots of examples online. These fellow authors also know about the ups and downs of writing. For the most part, they are happy to give other writers their support and encouragement.
Many of the regular hashtag prompts are for tweets from or relating to works in progress. I consider Discord's Child and Discord's Apprentice to be parts one and two of a larger work, The Exiles of Ondd, so I often mine them for tweets to join in. It's occurred to me more than once that if I'm not careful I'll tweet spoilers, if not the whole novel. The tweets are rarely exactly as they appear in the books. They have to be tidied up sometimes to make sense without the context. If they receive likes or retweets, it gives me a real boost.
Of course, there's no real danger that anyone reading them out of order and spread over months is going to put together a complete novel, unless they're really good at jigsaws–better than me, at any rate. I follow many authors who tweet extracts from their novels, and unless you already know the plot you wouldn't be able to guess it. The more that's tweeted, the more intriguing it becomes.
Maybe I should consider putting Discord's Child online as daily tweet-sized episodes, or use the tweets as quiz questions, such as which chapter is it from, or which character is speaking? Hopefully, my efforts would spark readers' curiosity enough to look at the full book.
Here are a few hashtags you might find interesting if you'd like to have a go yourself: #SlapDashSat #SciFiFri #BraveWrite #Sunscribbles #vss365 #MuseMon #2wordprompt #1lineWed and #FictFri. #TheWritePrompt posts a selection with the themes each day.