1) Google website loading speed test: https://developers.google.com/speed/pagespeed/insights/

2) Smush is the Wordpress plugin which will make your images load faster: https://wordpress.org/plugins/wp-smushit/

3) 9 Reasons a Book Was Rejected for a BookBub Featured Deal: https://insights.bookbub.com/reasons-book-rejected-bookbub-featured-deal/?utm_source=pemail_reasons-book-rejected-bookbub-featured-deal