Planning and preparation prevent pretty poor performance right?

Map and compass in waterproof case
Charged phone, spare battery, spare phone and or a phone charger
Water proof phone or waterproof bag
Route map with emergency exit points and plan for emergencies
Spare bad weather clothing
Spare emergency food / water
Plastic lightweight poncho
Emergency whistle
Emergency foil heat retention blanket
GPS or location device Mapping/Location app on your phone (for emergency use)
A route card left with someone
First aid kit that has a triangular bandage
Waterproof pad, pencil
Walking poles
Watch, ideally waterproof and or GPS enabled.
Spare gloves and headwear
Waterproof jacket and or trousers if the conditions dictate

Ensure that you check the whole area around the route that you are going and make a note of exit and emergency routes, roads and buildings that may afford some safety in the event of emergency.