I still generally attempt to follow the rules established by Edward Tufte in The Visual Display of Quantitative Information. Basically, Tufte used the idea of

I still generally attempt to follow the rules established by Edward Tufte in The Visual Display of Quantitative Information. Basically, Tufte used the idea of "ink", classified into two groups, data ink and useless ink. The goal is to have a graph with as little useless ink as possible; where every bit of information visible in a graph (or table) is relevant to the end output. To this extent, he recommended dumping axis lines where unneeded, labels, keys, gridlines, and many more things. LaTeX tables, by default, tend to look like what Tufte proposed, which is probably why LaTeX tables look so damn good compared to the HTML defaults