If you're an American, and you want to stop Trump, it's important to be actively involved:

• Check your voter registration - there's been an active effort to purge voter rolls, and if you moved or changed name, you'll need to register again anyways
• Talk with people you know about voting for Democrats up and down the ballot. Personal endorsement matters.
• Volunteer — it makes a real difference
• If you can afford it, donate to the Biden campaign. Even fairly modest amounts of money from a lot of people add up to being able to hire staff and run ads.