How to speed up initial backup?

What files should be excluded from
“Excluded Files and Directories”
to streamline backups for an uncomplicated blog?

I started a backup at 3:00 PM today and at 11 PM it was still running so I stopped it.

8 hours???

http://oldguyblog.net/
weaver 2 theme

Please advise.

TIA

https://wordpress.org/plugins/wordpress-backup-to-dropbox/