Pause and resume the download
Change Steam download region
Clear Steam download cache
Limit bandwidth usage in other apps
Use a wired Ethernet connection
Restart Steam
Restart your router and modem
Close background downloads and uploads
Disable VPN or proxy
Check for disk space and disk health
Install games on an SSD
Change Steam download limits to unlimited
Update network drivers
Disable antivirus scanning temporarily
Try downloading at off-peak hours
Verify Steam is not throttled by your ISP
Set Steam to high priority in Task Manager
Flush DNS and renew IP address
Disable Windows Delivery Optimization
Reinstall Steam if the problem persists