Compress images before adding them to the PDF
Reduce image resolution
Convert images to JPEG instead of PNG when possible
Remove unnecessary embedded fonts
Use font subsetting
Delete unused pages
Remove blank pages
Flatten annotations and form fields
Remove comments and metadata
Optimize PDF for web or smaller file size
Use PDF compression tools
Save as a lower PDF version if suitable
Convert color images to grayscale
Reduce page size if possible
Avoid scanning at very high DPI
Re-export the PDF with smaller export settings
Use vector graphics instead of large raster images
Remove duplicate images
Merge and compress multiple PDFs carefully
Use “Reduce File Size” or “Optimize PDF” options in PDF software
Recreate the PDF from source files with lighter settings