WordPress & plugins can't write files or create directories.

I have a Ubuntu droplet with LAMP installed at setup and I need to host a few different sites & domains there, so the first site’s path is /var/www/sitename.com/public_html, as opposed to the single-install WordPress setup. I also set up phpMyAdmin according to the DO tutorial, then set up the WordPress user and db, and imported the data. Then I copied the WordPress site up and unzipped it in place. At this point the admin and front end work except when needing to write a file or create a directory.

I then followed this tutorial – https://www.digitalocean.com/community/tutorials/how-to-configure-secure-updates-and-installations-in-wordpress-on-ubuntu – to the letter and didn’t hit any snags. It’s still unable to write to files or create directories, though. The admin looks fine but my front-end is completely unstyled because it’s dependent on a LESS plugin that needs to write newly compiled CSS files.

I’m a little lost at this point because I don’t know what else to do beyond setting ownership to wp-user:wp-user and making sure the permissions are set to the correct levels according to the Digital Ocean tutorial. Any ideas?

Thanks!