If you do one thing from the list, pinning a post (or several posts!) is the best way of preventing an account looking blank.
Pinned posts will ALWAYS show up on other servers, even if the account is brand new and has no followers at all.
You can pin up to five posts at a time on your profile, more info here:
https://fedi.tips/how-do-i-pin-my-posts-on-my-mastodon-profile/
(By the way, pictures aren't necessarily indicative of anything as a lot of blind users just leave the profile picture blank.)