Implementing async work requires a cultural shift. It's the hardest part, much more than picking the right tools or agreeing on some common practices.
Fighting the way society wired us is the hardest thing. Up until 1y ago, I still felt “guilty” if I went to the gym mid-morning after a 3h work session. I did it but did not feel great about it.
A lot of places that implement remote do so with an underlying mistrust for their own people. Leaders doubt how much people are actually working, and colleagues joke about that coworker that is always offline on Slack. These things contribute to feeling observed and judged and nudge people towards the standard 9-to-5 schedule, even if remote.
You notice the way we are wired in some little spontaneous stuff that comes up in conversation. Like saying "sorry" if you are offline when pinged in direct chat. People should not be apologetic if that's the way the team has decided to work.
It comes down to not stigmatizing people that use the freedom remote work gives them. We are working on this together, we have defined the game rules, and we will win if we stay honest, trust each other, and are committed to the company mission.
Leaders should judge by output, not by perceived working time.
Tools
Tools are important too.
Mute notifications on Slack by default by changing your schedule in settings or using the /dnd command. Only use DMs when necessary. Use Telegram/Whatsapp for emergencies, so you remove that stress too, someone can reach you if it's really important.
Another big one is switching to written by default. We still need to get there, and we may never will because doing the occasional meeting still works at our size. We try to write things down as much as possible, especially for strategy memos, proposals, issues. You name it.
Written by default makes a huge difference on the receiver of a message, especially if offline while receiving it.
Imagine receiving this on Slack:
"Hey, found this bug on our staging environment. Here are 12 screenshots and a vague explanation of what happened"
vs
"Hey, found this bug and logged it here with all the details, some screenshots, and detailed repro steps: https://..."
As the receiver, you feel less in need to respond immediately and are confident you won't miss that value report. It's the way to go.