1. not checking equipment prior to launching and fishing (bilge pumps beings a major one)
2. not having the proper equipment (gps, radar, charts, RADIO!!!)
3. not knowing how to use the equipment
4. not watching the weather
5. not paying attention to changing seas and weather closing in (the thick fog of summer as an example)
6. going places in a boat ill-suited for the normal conditions.
7. FOLLOWING CHARTER BOATS!!!!
8. no respect for the ocean
9. BOOZE!!!!.... you drink offshore, you're a freakin' idiot.
10. giving gps coordinates over open radio channels (VHF) or over the internet

remember, conditions can change in the blink of an eye. calm, flat conditions can become plain nasty in a very short time. halibut fishing, i am constantly amazed at the boats people take out 20-40 miles offshore (sorry, ski boats just aren't safe out there). what's fine in flat conditions just won't cut it the time it kicks up (and it will). when the normal may weather returns, there will be some deaths.

yeh, i added some things that aren't about safety... but that just show a lack of respect for your fellow fishermen.

chris