Plot Y vs X (check for linearity, outliers)

He is talking about bivariate Y and X scatterplots.

I was wondering what others think about this. Since I have 20 thousand or so points sometimes (and always thousands) I usually don't worry about individual outliers. And I am not sure it makes sense to look at bivariate relationships this way when you have many regressors.

Maybe you should instead look at partial regression plots?