There is a fairly consistent theme within the OpenVPN support channels, IRC, the web forums, and the mailing list. The novice users of OpenVPN generally ask the same questions. Most common issues can be resolved by simply dutifully reading the OpenVPN manual (http://openvpn.net/man) and taking notes. Although this book aims to inform the reader of additional techniques and tools, the man page is a considerable wealth of knowledge, and the close scrutiny of its contents will be beneficial in the long run.
Based on questions found in IRC and on the forums, the novice OpenVPN administrator struggles most with identifying the root cause of a problem and is generally lost with how to find that cause. The vast majority of problems can be grouped pretty easily into a small subset of issues, often quickly realized with initial configurations:
Certificate problems
Incompatible
tun/tapconfiguration settings between a server and a clientIP range conflicts with VPN and remote...