For what it's worth my experiences have been that the aiming of the sensor can be critical - aim at the ground or the sky and it will greatly reduce your triggers. In general the camera should be at about knee height facing horizontally out from the tree or post, don't tilt up or down.
Be realistic about the flash range and the sensing range - for many cameras both are about 40 feet maximum with 15 - 20 feet being around optimum. That's only 5 or 6 big steps which isn't very far at all if you are wanting to try and cover a 4000 acre lease. Given this you have to get the deer to come to the camera and so picking a good spot is important. I have a spot where I will see over 100 photos per 24 hour period at this time of year whereas another very similar spot only a short distance away will only return 15 or 20 photos in a month.
Trust what the camera is telling you - if you aren't getting any photos then it is likely the camera is working fine but it is in the wrong place. This doesn't mean there are no deer, just that they aren't appearing where you think they are.
I've found it best to place the camera low down aimed exactly horizontal on areas with relatively low vegetation. Avoiding areas where the heather is 2 foot deep can greatly limit locations but will also give you a much better chance. If you place it high up then generally you have to tilt it down slightly and while there are some circumstances where this works in most case it has a significant impact on your sensing range.
So, for example, this location had sod all triggers despite a lot of deer using this ground and if you look carefully the centre of the photo is actually aimed about 20 feet in the air, the camera is too high off the ground and the heather on the ground is nearly tall enough to cover most deer. I think it was a bird that triggered it on this occasion:
This area produces lots of triggers - camera is about knee height and aimed straight out with the centre of the frame about where a deer would be plus low vegetation allowing easy sensing:
The advantages of a fast trigger - you can catch fast moving deer before they are out of shot and you also catch them quickly when entering shot which makes a fast trigger ideal for setting up on trails or other areas were the deer are moving: