To increase reproducibility of your data projects from the start, I recommend setting up a project in R, include version control with git, and writing reproducible reports with R markdown.
Soon: a step-by-step guide with how I set up my projects for reproducibility.
Chris Makler built a great website with customizable graphs for many economics concepts: econgraphs.org
Nick Huntington-Klein has a great post with animations explaining statistical tools of causal inference: causal graphs
Pol Campos-Mercade has written a useful guide on power analysis through simulation (in Stata): guide
"Seeing Theory" is a great website of interactive tools to explain probability & statistics. From basic probability concepts to Bayesian updating: Seeing Theory
Chris Roth and David Schindler have put together a website with a collection of advice for PhD students in economics: EconGradAdvice
Amma Panin and Marco Schwarz have collected a list of behavioral and experimental conferences: docs.google.com