The LNCS format does not print nicely on A4, because the LNCS book pages are much smaller. However, most preprints, your own LNCS papers, and papers you get for reviewing are formatted for A4. Printing one page per sheet wastes a lot of paper for the wide margin, but when you print two pages per sheet you can hardly read the small text any more. Here is a fix:
pdfnup doc.pdf --nup 2x1 --trim "-6cm -6cm -6cm -6cm" --delta "-18cm -18cm" --scale 1.8
Update: Formatting your PDF right
It is even better if you already set the right paper format when creating your PDF. With appropriate printing settings, that gets the print right without the adjustments mentioned above, and it makes screen reading more convenient. Markus Kuhn explains how. However, his measurements didn’t work for me; instead of 92 112 523 778 I had to use 91 71 521 721.