More Doodles that you can put together to make your own designs.
Coffee and Tea Doodles is a font of coffee and tea things-- perfect set of illustrations for coffee or tea shop menus, ads, invitations, etc. http://www.outside-the-line.com/shop/coffee-tea-doodles/
The golden ratio should not need any introduction to those who have studied math and design in school. Some designers apply these mathematical concepts to come up with more visually appealing works. This infographic from companyfolders.com covers a few golden ratio facts:
Paper airplanes are fun to draw | Linda Rea | Flickr