change your profile pic and bio the first thing, otherwise you'll seem like a bot and everyone will block you. Selfies likely will get you blocked as well due to the sexygirlbots. You need to seem human to survive here
set your dashboard settings to chronological. The algorithm here is so dysfunctional it just doesn't work. You'll see the same posts only and of some post is really popular, chronological view will show it anyway because everyone will reblog it
set your community label and tag filtering preferences. Tumblr is very customisable, so tailor it for yourself
if you're on iOS, log in through browser once and disable filtering in iOS app. Otherwise almost everything that's not right-wing family friendly will be hidden from you in the iOS app
disabling anon asks can be a good idea
there are no public view or follower counts.
REBLOG. Likes are inherently nothing but personal bookmarks. They don't do anything. Only reblogging does.
there isn't such a thing as spam liking/reblogging. People are generally overjoyed you've enjoyed everything they've posted
tag relevantly. You can add up to 20 tags and they'll be searchable on original posts. Don't spam tag with unfitting tags though, it'll get you flagged. Tagging reblogs is for your own housekeeping on your blog.
you can have side blogs if you like to keep your reblogs and posts within a certain topic/fandom