Here you find some Links to Tutorials, learning Videos for some Modeling-Software

Modeling Software Tips

Fusion Playlist:

https://www.youtube.com/playlist?list=PLmA_xUT-8UlJHEjhbzUowAKzlgq_cV5Z7
https://www.youtube.com/user/AutodeskFusion360

Fusion Lessons

English

http://help.autodesk.com/view/fusion360/ENU/

German

http://help.autodesk.com/view/NINVFUS/DEU/

Chinese

http://help.autodesk.com/view/NINVFUS/CHS/

Japanese

http://help.autodesk.com/view/NINVFUS/JPN/

123D Tutorials

https://www2.warwick.ac.uk/fac/sci/wmg/about/outreach/3d_design_printing/cad_tutorials/

Other Links

http://www.core77.com/posts/65318/How-to-Design-Snap-Fit-Components (PDFs available in Further Reading) https://formlabs.com/blog/designing-snap-fit-enclosures/
https://formlabs.com/blog/how-to-create-models-larger-than-your-3d-printers-build-volume/
https://pinshape.com/blog/design-for-3d-printing-easy-snap-fit-parts/
http://machinedesign.com/fasteners/fundamentals-annular-snap-fit-joints
https://www.stratasysdirect.com/resources/injection-molding/
http://www.javelin-tech.com/3d-printer/coring-3d-printed-parts/
https://www.youtube.com/watch?v=IyvFpuFeDYc
http://support.ponoko.com/hc/en-us/articles/220290728-How-to-design-3D-printed-pin-hinges-No-assembly-required