Pause and resume the download
Restart Steam
Restart your PC
Check your internet speed
Use a wired Ethernet connection
Close other apps using bandwidth
Disable VPN or proxy
Change Steam download region
Clear Steam download cache
Limit bandwidth settings in Steam
Remove download restrictions in Steam
Update network drivers
Disable Windows Update during downloads
Temporarily disable antivirus web scanning
Make sure the drive has enough free space
Install games on an SSD
Verify no background downloads are running
Try downloading at off-peak hours
Flush DNS
Reset your router
Check for ISP throttling
Reinstall Steam if the issue persists