Here is a free checklist which is provided on a printable PDF from a chaps website in the UK. As he says, you don't need to take everything on the list, it depends on where you are fishing, the conditions. But at least use the list to think about it.
Kayak Fishing Safety Checklist
PFD with pealess whistle attached
Wetsuit Correct for season/water temperature
Flares (Smoke) Orange for daylight, Red for nightime
VHF Radio Check battery level
Mobile Phone Backup for VHF Radio
Diving Knife/Pen Knife
Basic First Aid Kit
Waterproof Torch Check batteries
Drink and Snack
Change of Clothes in Dry Bag
Tides If in doubt check with Coast Guard
Paddle Plan Give shore contact details of your route
Return Time If delayed call shore contact
If in doubt, donít go out!