Download the Human Factors Design Standard

Even if you don't design aircraft, the Federal Aviation Administration's Human Factors Design Standard, is an invaluable (and free) reference for design practitioners. 

The complete design standard is large (10MB) and comprehensive - "an exhaustive compilation of human factors practices and principles" - but it provides succinct and tactical, evidence-based information.  For example, concerning touchscreens, fourteen specific guidelines are given for button size, labeling, position, dead space, etc, but the need to test with representative users is also recommended to keep these rules grounded in reality.

In 2007 the FAA added draft updates related to interface design, including displays and non-keyboard input devices (e.g. mouse, joystick, touchscreen). 

A brief, anonymous survey form is required to download the Human Factors Design Standard (HFDS).  Once past that, you may download the entire document or any of the 15 individual chapters or drafts, ranging from Alarms, Audio and Voice to Anthropometry and Biomechanics (a particularly strong section of the document).

Sparsely, but appropriately illustrated, the HFDS gives the actionable guidelines that so many product designers and students are desparate to find in a single location.

PS - Experimenting with larger font size for better readability on recent posts.