of course I am asking for tricks that are "hidden", i.e., people who read the output(paper/thesis) cannot see what I am trying to do...
I am currently writing my thesis in font 12 and I am using Vertical spacing: MedSkip, Line spacing: Double and the following latex preamble (provided by Stefan_K) for math formulas spacing.
Sounds to me as if you have loads of additional space already… there is only so much space you can insert before your document starts to look really weird…
You could of course make the margins bigger. Then you have less text on every page and the document seems longer. Adding lots of figures with lengthy captions would also enlarge a document.
Personally I would not bother about other people's theses but focus on letting mine look good. Ideally it should be a pleasure simply to look at it... (which is a huge topic to discuss and disagree upon )