Turned in a few over the years. Reported a couple of doofuses that killed 2 sub legal bulls at the same time. When F&W followed up with them, they discovered they had poached a cow a few days earlier, and also over harvested black bears. My hunting partner casually took pics of them with their ill gotten animals.
I have turned people in for wanton waste (left an entire carcass) and they paid the price. I'd turn my mom in for that (course she wouldn't do that but you get the point)
Now days when I'm in the field, I use my camera or smart phone to grab a pic of anything that looks out of place. You get a time stamp along with the pic. Say you come back a day or 2 later and the ravens alert you to a carcass. Now you should have a pic of a vehicle, license plate, and maybe even....gasp...poachers. I keep a pad and pencil in the truck also, and take notes.
Talking with other hunters you know that are in the same area can result in sharing of information that helps put the pieces together.
That's the best way to get a handle on this stuff. F&W ain't gonna catch them on their own. Too much area to cover, and too few officers. We have got to be the eyes and ears. And Narcs too, I guess. Sucks to have to call somebody in, but if you don't make the call then don't expect too see your hunting area being over run with 50" plus bulls.
Be proactive folks.