How do I get started with software development? I can read and write several languages, but don't know anything else about developing software. What tools do I need to get started? What are the things I should know?

There are also plenty of great blogs on fields that are usually related to programming and are relevant for developers. For example, Matt Cutts is the place to go for all things SEO, check out Both Sides of the Table or Sam Altman's blog for insight from VCs, and read Sean Ellis for ideas on how to grow startups.
At https://svitla.com/blog daily articles published by expert developers from around the world. Articles include tutorials on really innovative solutions to cool topics (e.g. object detection algorithms for mobile, social network data mining for predictive analysis, and using machine learning to predict gas prices, to name a few), in-depth analyses of new technologies, explorations of emerging technologies and recent tech trends, tech lifestyle posts (especially about remote working and digital nomadism), and more.