Speedcubing

/ˈspiːdkjuːbɪŋ/, noun
Solving Rubik's Cube and other twisty puzzles in the least time possible.

Welcome to the obsession. My current speedcubing method for Rubik's Cube is the Fridrich method (CFOP) with the following techniques or additions:

• Occasional extended cross and other block approaches for F2L
• F2L cross on bottom or left
• Many empty-slot cases and other F2L tricks; multiple algorithms to minimize rotation/regrips
• LL control: occasional partial edge control to avoid dot OLLs, some OLL skip tricks
• Easier COLL cases when appropriate

With this method I set multiple world records between 2004 and 2006 in both single solve and average of 5 for 3x3x3 speedcubing.

I'm a beginner. How should I learn to speedcube?

Full CFOP is quite advanced and is meant for cubers near 30 seconds who aim to be sub-20. See this article for one suggestion on how to begin.