Disclaimer: while I have had some luck finding deer while still hunting Muleys, but I am definately not an expert. I will say right up front I have never shot any of the deer I found while still hunting, but have seen some 130-140" bucks that I have passed on.
Dislaimer complete; here are some of the observations I have made:
1. Deer I have found bedded in the timber seem to gravitate towards some type of terrain feature. Example: I have found deer bedded in the shadow of rock outcroppings or uphill from game trails or clearings.
2. Just because it is heavily timbered doesn't mean the deer feel secure. The timber that has difficult access because of natural obstacles is more likely to hold deer. I have found deer by looking at topo maps and finding the timbered areas that are isolated by cliffs, finding my way around the cliffs, and then working my way back towards the cliffed out area.
3. I try and look for ideal bedding spots, but maybe more importantly I am looking for the likely escape routes, because more often than not when I see a deer still hunting it is already alert to my presensce and is deciding if it needs to run. I then have to assume that if it was a big buck it would already be moving out. I got the drop on a 140" 4 point in the Bighorns a couple of years ago because I coaught him trying to sneak out the back door on me and I was able to reposition as he came around the face of a rock outcropping. I passed him up, but before I did I put him in the crosshairs at about 35yds.
4. A trick I learned in Afghanistan when we would go into villages we thought might have some unfreindly characters that might want to run and hide in the adjacent mountains. If you have a hunting partner in overwatch of a patch you are going to still hunt, they might be able to see where any deer that get spooked come out, allowing you to make a move on them once they have settled back down. Alot of times a deer that thinks he got away from you clean may not go real far, but you are still going to want to give them plenty of time to settle back down. Kind of a mix between Stillhunting, a Drive, and Spot and Stalk (if you are lucky).
5. Speed (or more accurately a lack of) is very important. I have been told you should where the same wieght of clothing you would wear if you were sitting still in the same weather, and you should walk slow enough that you don't sweat. I am not sure I follow this rule, but I try.
6. Don't discount the importance of optics. I pull up my binoculars every couple of steps and scan cover, Terrain features, escape routes for eyes, ears, antlers, and hide.
There is a good article By Ryan Hatfield on still hunting in EHJ. I will try and find the issue # (Maybe around #119??)
Anyway,
Hope this helps
Ross