I have a printer (Dell v305), and it can't print more than one page per sheet.
How can I print to this printer so that it will print, say, 60 pages with 15 sheets of paper? (double sided is 30, and two per page is 15)
You are asking two questions here:
The second question is easily answered and is valid for all printers (not just the v305):
Double sided printing is only possible by either having a printer which supports it in hardware (it needs the rolls and wheels to manually turn the paper over and print it again on the other side), or by manually turning the paper and feeding it back into the paper.
The manual part can be optimised by first printing half of the pages (e.g. all even pages) and then manually putting the paper back in (reversed) and printing the remaining (odd) pages. There is not need to do this for every sheet of paper, but you will need to it once per print job.
The first question is a bit harder and it also has two answers:
The easiest way to massage your output might be to print the PDF to a PDF printer. That seems redundant but you can use that to change some settings. An alternative is to use ghostscript (for postscript printers).