I've written a small ebook aimed at technical people to help them learn how to design 3D printable parts.

It contains some basic introduction to FDM 3D printing (understanding the process, the applications...) and then guidelines to design parts that make the most of the technology.

The ebook is open source and there is a repo where I am uploading all the images and 3D files used in the book so everybody can use them in their own projects: https://github.com/Bitfab-io/how-to-design-for-3d-printing-ebook

Also, the official ebook page is this one: https://bitfab.io/how-to-design-for-3d-printing-ebook/