Tips and tricks
Beta testing on Android
Wanna be on the bleeding edge (and have an Android device)?
Sign up for the Android beta version by visiting this page in the Play store, scrolling down, and opting in. You can expedite actually getting the beta by subsequently refreshing your apps.
No info re any iOS beta at this time.
Posting and crossposting
Hit enter three times to create a new post in the same, er, thread
You can control who can reply by selecting an option to the left of the 'Post' button when drafting a post: Anyone (the default), Profiles you follow, or Mentioned-only.
Note that this doesn't change the visibility of that post; all your posts are publicly-readable by default!
You can easily share a pic from your Threads to your Instagram account
Following
Within the feed, hit the + sign on a user's avatar on the left to follow them
Misc
You can see what 'number' you are (signups-wise) by looking at your Instagram profile