Ironically, despite being a mixture of rather obvious commonsense stuff with idiosyncratic practical tips, this one page of tips is probably a more important contribution to humanity than my entire thesis (because the results of my thesis are only applicable to people in a specialized field, whereas many, many people do the sort of data analysis that these tips would help with).

Please note that although i say 'big data' here, what i really mean to address is situations where your analysis subroutines take more than a couple of hours to run, regardless of how much or how little memory/storage space the data takes up.