Use a PDF compressor tool
Reduce image resolution
Compress or downsample images
Remove unnecessary pages
Delete unused objects and metadata
Save the PDF as optimized for web
Convert images to JPEG instead of PNG when possible
Use grayscale instead of color
Embed only required fonts
Remove annotations, comments, and form fields
Flatten layers and transparency
Print to PDF with lower quality settings
Split large PDFs into smaller files
Recreate the PDF with smaller source files
Use a smaller page size if possible