Here you will find a compiled list of useful links to improve your understanding and gamplay in StarCraft II.
Liquipedia - A StarCraft II wiki maintained by TeamLiquid.net. Use it to increase your general fund of SC2 knowledge and overall strategy.
Day Daily #132: Back to Basics: The Mental Checklist - The most basic notions of actually playing the game of StarCraft II. Highly recommended.
Day Daily Newbie Tuesdays - A series dedicated to examining issues that newer players face.
more to come...
Watching replays is a sure way of learning what strats work, if not why they work.
There are a multitude of sites offering replays, offering slightly different populations and search option. Find your favorite.
Original thread by Ampersand, moved from old site