Machine Learning Algorithms: Which One to Choose for Your Problem by Daniil Korbut via @statsbotco

Intuition of using different kinds of algorithms in different tasks.

I like this as it clearly explains which machine learning algorithm to use.

Practical Guide to Principal Component Analysis (PCA) in R & Python via @AnalyticsVidhya

Practical Guide to Principal Component Analysis (PCA) in R & Python by Manish Saraswat via +Analytics Vidhya - Do you get stuck when a dataset has too many variables? Then you must work your hands on PCA to overcome these. Here's a simplified practical guide on this, with implementation in R & Python.

Great guide and worth reading as a reminder.