A Checklist for Developing Defenses

Step	Description
Gather your requirements.	Before selecting an appropriate solution, it's important to define your requirements. Determine whether your requirements need a network-based solution or a host-based solution. If network-based, then are you simply interesting in detecting attacks, or in blocking them as well?
Build a list of candidates.	Based on your requirements, build a list of potential vendors based on their offerings. Take into account the stability and track record of the vendor, as far too many have been burned when procuring products from vendors that no longer exist.
Evaluate candidates.	It is important to perform an evaluation of potential products in order to determine the best fit. Most vendors will provide evaluation platforms in order to facilitate this.
Deploy your solution.	Once procured, deploy your solution as recommended by your vendor.