Really cool site where you can download design resources.
https://qeaql.com

Stripe. A great payment solution with plugin for WooCommerce.
https://stripe.com/se
https://wordpress.org/plugins/striper/

A quite complete ecommerce checklist (In Swedish)
http://bigorangebutton.se/checklista-optimera-din-e-handel/

A nice guide to Google material design.
http://designmodo.com/material-design-resources/