This is a somewhat perplexing question. Please see my article in the Philippine Daily Tribune (December 6, 2008).
The short answer is that we cannot firewall an open economy. We can do some things to make it resilient, but these are long-term fixes. But short-run policy mistakes, such as an overly tight monetary policy and an overvalued exchange rate, will weaken the economy.
Of course, we could turn inward, and take the protectionist path of Myanmar, North Korea, and Cuba. But this is not a serious option. It would simply keep us forever poor.