Hi.
1. Limit yourself to, say, a dozen trigger words. If you got more, cross some out.
2. You ARE right: any word can be a trigger word. Perhaps something at first glance off topic is a way for you to relate yourself to the topic at hand.
3. To begin with: look at the cover, in the foreword and/or at the table of contents. Some word/phrase that is repeated?
4. Look at the glossary: Some definitions that seem more important than others?
5. Look at the index: Any words/phrases with a LOT more page referred to than others? Any words/phrases with long sub-anythings (for example: word: activation, subs: mind probing, super reading, skimming)?
6. Try to lay out your trigger word graphically (for example a mind map or a cluster). Do you see any connections yet? During activation, you can fill in gaps, add on to this graphic or rebuild it from ground zero.
Hope this helps,
Jens