I know a thing or two about creating identities. The first thing you need to do is research.. and build a person, which means having a bunch of additional assets tied this person. An e-mail account, a blogspot, perhaps a twitter handle, add that all to the FB account, and be consistent with your language and opinions. Give your identity some background, find names and places that have enough additional matches so that if your identity is doxed, it has so many hits that it would be hard to determine an end user. Also, don't get trapped.. use proxies when chatting, making posts, etc, so that location information matches your profile. If your identity is from Germany, connect through a german proxy and enable location tagging on your wall posts. That's just a few pointers to get you started.