Fuel checks (draining) is an external check. This is preferably done with the tanks full or freshly refuelled, to check integrity of the fuel you've just taken onboard.
First flight of the day, I like to check for water while the aeroplane is stil in the hangar - before it has moved. If there is any water in the tanks, it will have had plenty of time to collect at the bottom of the tanks and will show in the fuel check. Can't argue with also checking after a fill-up as well, though, to check the integrity of the fuel you've just uplifted as Chilli says.
As for check lists, best done mentally in simple aeroplanes IMHO, especially if yu are familiar with the type.
SSD