Advice for Folks Doing Political Research

I've seen some remarkably one-sided books about political movements lately. For the benefit of those writing such books, fiction or nonfiction, here are some notes on the characteristics of groups.

Every group has:

Some foundation idea or ideal.
You may have to dig for it; it may be repulsive to you; but it will be there. If you can't figure out this ideal or constellation of ideals, you will never understand the group in any real way.

Extremists, moderates, and somebody who joined up because his friends did.
An extremist group will have real loonies on its fringes and a moderate group's extremists be hard to pick out, but they're always there. The uncommitted may have interesting things to say.

Members of different groups: different churches, cultures, etc.
The more homogenous the group, the more its tiny differences matter to its members.

Intra-group politics.
There are always at least two factions and an out-group, even if the group was just formed five minutes ago.

Members with enemies within the group.
The more prominent, the more enemies.

Gossip and criticism.
The more idealistic the group, the more criticism of failures, whether public or personal. The more tight-knit, the more other people will know about these failures.