I was learning how to be an intel officer, one lesson I learned was that the best source of intel information was our own troops. Now, the fact is that ordinary soldiers may not be the BEST source but they are a critical source. In my day, many intel folks didn't bother to do the 2 key things needed to take advantage of that source:
1. Brief the troops on what to look for whenever they went on a patrol or operation. And
2. debrief them on what they observed when they came back.

Cheers

JohnT

PS Also always ask the local civilians what you want to know. they may actually give you useful answeres.