For documents produced from LaTeX, you can force Type 1 fonts either by using dvipdfm to produce the PDF file direct from the DVI file, or by including a \usepackage{times} command in the LaTeX file (to use PostScript, rather than LaTeX, fonts) and then using either dvipdfm or the usual dvips and ps2pdf .
If you are including images in a document and they are of poor quality once converted to PDF, you need to change the way they are encoded in the PDF document by adding the lines:
systemdict /setdistillerparams known {
<< /AutoFilterColorImages false /ColorImageFilter /FlateEncode >>
setdistillerparams } if
to the .eps file containing the image, just below the lines that start %%.