Step 1: Drill hole
Step 2: Preparation
Step 3: Place one side of the tyre over the rim
Step 4: Finishing off
Painting the valve cap of the flattened inner tube will make it easier to identify.
When you get a puncture - simply remove whatever caused it and fully deflate the tube. Then inflate the flattened tube and get yourself home. You may have to hold the valve stem of the punctured inner tube in place until the other is inflated enough to hold it there.
Things to consider - Drilling a hole in the rim will weaken it, ensure that the results of your drilling will be strong enough and avoid drilling directly opposite from the original hole creating a weakness accross the line of symetry.
see also -
For how to make your bike rust proof see