Start by slicing the shallots. You can do this by hand or with a mandolin, but you want them to be even thickness. They should be about as thick as a dime!
To ensure crispy shallots, make sure you're cooking them low and slow. This will allow the shallots to crisp up without getting soggy or soaking up too much oil.
Don't throw away the oil after you fry the shallots! The cooled oil is amazing for salad dressings, roast vegetables, stir fry, and finishing soups and meat dishes.