Step 1: eliminate centralized services. This would only make Bitcoin stronger if it's already a functioning economy that doesn't depend on connections to the existing financial system. If you can't buy and sell Bitcoin with traditional currency, it becomes far less practical.

Step 2: make use of Bitcoin illegal. You know, "ban" it. It's a plaintext P2P protocol, not exactly magic. If you control the network, you can identify Bitcoin nodes and charge their owners, exactly how law enforcement can enforce laws against other illicit P2P traffic. This would drive any remaining die-hard users to services like Tor.

Step 3: if Bitcoin is somehow still popular enough to be considered a problem, block Tor.