Mima is right, we should link to toots. It is kind of a way around the absence of "quote tooting".
However, I have recently learned that, by design, Mastodon doesn't automatically share all toots across all instances, and we are essentially not seeing most of the Fediverse depending on how active people on our instance are.
If you really want to make sure everyone that can see your toot can also see your quoted toot, boost it first. Or use a screen grab.