The whitepaper Start Small, Grow Fast by Demed L’Her, Edwin Biemond, and Ronald van Luttikhuizen ranks 3rd in the Top 10 most popular OTN articles for architects (2012). The full Top 10 including links to these articles is listed here.
The whitepaper explains a set of pragmatic best practices for deploying a simple and sound SOA footprint that can grow with business demand. The paper contains details about administrative considerations, infrastructure considerations, development considerations, and architectural considerations.
You can find a companion checklist that summarizes the Oracle SOA Suite best practices in a previous blog.