Depends on how much $$$ you want to spend and/or how radical you want it to be.
For general purpose I'd think along these lines:
1. Upgrade to mud/snow tires
2. Prepare a H3ll box and keep it in the Jeep. the list of things to go into H3ll box should include at least:
a) extra fluids oil, trans anti-freeze
b) spare set of hoses and belts (I just replace the ones that are on before they need it and keep older ones as spares)
c) tire plug kit & air compressor
d) spare set of fuses and an assortment of electrical connectors with a crimping tool
e) a set of tools
f) jumper cables
g) 2 pairs of gloves 1 cotton and 1 leather
h) a come-along with a set of chains and 20' snatch strap along with a tree saver strap
i) spare set of spark plugs and a rotor
j) duct tape and electical tape
k) bungy cords