I think you are asking about what to do with headers in tabular data, if so, here are my thoughts:
Headers should be one column/one row and only one column/one row. If you have to label across rows, simply add the name of the label to the rows you want to apply it to.
This does lead to extremely long headers, so also another thing to apply here is some deductive reasoning. Do you truly need to say all of that in the header? In some cases, headers are redundant. And in these cases, I simply delete the text entirely. When they are necessary, I go with the longer headers.
Just my opinion. I've found one row/column headers to be much more easy to work with across many platforms and technologies.