Hey, new friends/followers! Just a couple of tiny pointers as you try out Mastodon -- I HIGHLY recommend signing in via https://elk.zone on the desktop and using one of the third party apps for iOS (I’m trying out Mona and Toot right now) for better interfaces that'll feel more familiar to Twitter users.
Elk

A nimble Mastodon web client

Elk
One Mastodon quirk is that following people who are not on your server can sometimes require an extra step -- manually copying their username, putting it into the search field, and bringing them up that way. It's a pain, and a quirk of the whole federated thing. But once you're following them, you should be able to see all their posts normally.
This also creates an extra step when you're browsing other people's follow lists to see who to follow - those lists will often only display people on your server, and you have to click ANOTHER link to go to the person's profile on THEIR server to see their full list of follows. Again, a pain, but with a few clicks you can get where you need to be.
The other main limitations of Mastodon from the perspective of Twitter users is that it doesn't have quote posting by default and search is not comprehensive. Both of those things may decrease harassment and dogpiling. But they also can frustrate legitimate discovery/sharing. Supposedly a version of quote posting is in the works in a future update.
All that being said, Mastodon's probably my personal favorite of the various Twitter alternatives. It's been around a while - I've had an account since 2017! And with the above notes excepted, it generally works pretty great for me. One big ADVANTAGE is that you can follow hashtags. As a 35mm film photographer, #BelieveInFilm is my fave and you should check it out! :-)
Also worth noting: private mentions here are not end-to-end encrypted AND if you include anyone's handle, they're included in the message whether you addressed it to them or not. So if you're TALKING about someone and use their handle, they will get the message. PROCEED WITH CAUTION!
@gregpak
situation is a bit different for all those who are on calckey, foundkey and pleroma: all three of them boast non-federated chats, with calckey and foundkey chats being interoperable
#fediverse #calckey #foundkey #pleroma
@gregpak Elk is a pretty slick interface.
@gregpak thanks for the recommendation of Ivory. The interface is much more familiar. And thanks for the other mastodon tips on following folks. I wondered why I was only seeing short lists.