Here is a growing collection of tips, tricks, and techniques for the Arduino.
Arduino Tips & Tricks - Vidyasagar Academy Akola
Arduino UNO FAQ, Arduino Tips, Tricks, and Techniques
How to Code Your Arduino Board
20 Best Arduino Books of All Time - BookAuthority
Adding many sensors to one board - Programming Questions - Arduino
The 18b20 Temperature Sensor: Your Essential Guide for Arduino Uno
How do I Power my Arduino? - Robocraze
20 Best Arduino Books for Beginners - BookAuthority
PPT - Microcontroller Fundamentals PowerPoint Presentation, free
Troubleshooting Guide for Arduino - GadgetMates
Arduino for beginners- Introduction to Arduino (presentation