Nailing Night Exposures: Here's a guide to the rough settings you're likely to need for popular low-light subjects.
How To Use Brushes and Graduated Filters in Lightroom. Learn how to use brushes and graduated filters in Lightroom. Plus, enjoy an awesome Q.
How to Layer Lightroom Presets | Pretty Presets for Lightroom
99 Common Photography Problems (& How To Solve Them) @ Digital Camera World
Exposure Cheat Sheet made by a high school student.
Photo Editing Walkthrough