There but for the grace of God go all of us...
When we read, we scan. That's why it's easy to miss stuff when you're proofing.
A few quick proof reading tips:
- Always check large type eg headlines, titles closely.
- It's easy to scan over errors in caps - take a good look.
- Are figures, symbols, telephone numbers, urls etc correct?
- Cover lines below the text you're reading so you focus exclusively on that line.
- Read upwards from the bottom of a column if necessary.
- Check for what makes sense as well as for literals, spellings etc
- Ask yourself whether anything's missing.