Compress using a PDF optimizer tool (e.g., Adobe “Save as Other” → “Reduced Size PDF”, or online/commercial PDF compressors)
Reduce image resolution (e.g., 300 dpi for print, 150–200 dpi for screen)
Convert images to more efficient formats (use JPEG for photos; use lossless compression where appropriate)
Downsample images in the PDF (reduce pixel dimensions)
Use stronger image compression settings (lower JPEG quality slightly while maintaining acceptable readability)
Remove unused objects and embedded resources (optimize/“clean up” the PDF)
Delete unnecessary pages
Flatten layers and remove transparency when possible
Convert vector graphics to optimized vectors (simplify paths, reduce point counts)
Remove unnecessary fonts (subset fonts; embed only used characters)
Re-save/export with “optimized” or “web/smallest size” settings
Disable or remove embedded thumbnails and previews if not needed
Remove metadata (author, creation tools, XMP) if acceptable
Remove bookmarks, form fields, and annotations that are not required
Ensure the PDF is not a scanned document with full-page OCR images; re-export from OCR text when possible
If the PDF is generated from Office/print drivers, export using “Save as PDF” with minimal size settings
Use “linearized” PDFs only if it helps your use case (often for web viewing)
Split large PDFs into smaller files and compress each separately if appropriate