@Luvvie I like using Tusky! It has a great "delete and re-draft" feature.
You can migrate accounts between servers if you really want, but it can be a bit tricky technologically.
Different groups use CWs differently. If someone doesn't like how you use yours (or vice versa), you can always just block them. Lots of people use them like "subject lines" instead of only to hide only really shocking stuff. There's some drama/asshole stuff happening a little around this discussion. I wouldn't really sweat it.
Lots of people describe their images on here. If pictures load slowly, I usually read the description to see if I care enough to wait. It's a nice thing to do because I talk with some people who use screen readers, so I like to make sure they at least know what kind of picture I've posted when people are reacting to it.
Mastodon is not actually just one technology! It is an implementation of the activity pub protocol. There are lots of other little sites that implement this protocol, which means that they can all talk to each other. So, not only can you talk to people on other mastodon servers, you can also use your normal mastodon situation to talk to people who aren't using mastodon at all! This might be a little confusing, but you can think of it like being able to follow someone on Instagram from Tumblr. If you could do that. I don't remember the names of all of them, but Pixelfed is a federated "Instagram" style experience.
See more by looking at #feditips.
Also, hi! Nice to meet you! I'm Starless. :)