I felt the Instrument rating was the easiest check ride, but its also the one I studied for the most. Small corrections is what you've got to do. The scan probably breaks down a mile out because things get more sensitive, and you may panic. Get the GS and speed where you want it, and trim, trim, trim. And trim some more. This makes the small corrections you need to be making easier since you're not fighting the airplane. Like it was also said, slow it down if you can. I was taught to fly them at 90, but you could do it at 80, just make sure you figure the timing out right for the MAP. If the LOC is going left 5 miles out, give it a 5 degree correction, and see what happens. If it stops moving, I like to turn another 5 degrees, and turn back to the original course correction. When you trim and set the plane up 5 miles out or so, it will do most of the work for you. Just remember the 5T's. Time, turn, twist, throttle, talk. This is what I do, and I am sure many people here do it different:

FAF click the clock, throttle down to 1800 and put 10 degrees of flaps in, and start the decent. I already twisted the OBS in to the FA course WAY back on vectors. I already briefed the approach WAY back. So now at FAF, all I have to do is keep the speed and needles where I want them. Now just talk. Tell tower you're FAF inbound, accept landing clearance, and just concentrate on the scan, and make small corrections with trim.