Iceberg, the best hint I can give you about aiming is this (this assumes you have a positioner arm):
Start with your due south satellite (or as close to it as possible) and get it as best you can. In particular, concentrate on getting the elevation right.
Then go to something like AMC-7 (or as far west as you can get a signal) and adjust it for the best signal you can get WITHOUT touching the elevation. You can loosen the bolts on the pole and move the dish a little east or west (of course you'll have to move the positioner also) but at some point you will find a place where that satellite comes in perfectly by ONLY by moving the dish on the pole and tweaking the positioner arm.
Now you (temporarily) tighten the bolts enough to lock the dish on the pole and go back to your due south satellite and adjust the elevation (only) for peak picture.
Then you go back to the western satellite, loosen the bolts on the pole enough that you can tweak it again for best signal only by turning the dish on the pole and bumping the positioner motor.
The rule is, on the due south satellite, you ONLY adjust the elevation for peak signal. On the westernmost satellite, you ONLY rotate the dish on the pole to achieve peak signal, bumping the positioner motor a little after each movement to peak the signal (if you can visualize in your mind how your dish tracks the arc, this all makes a lot more sense).
Lather, rinse, repeat
until you can't get it to track the arc any better. This should give you the entire satellite arc
if your pole is perfectly vertical.
Note that if you can see a satellite closer to the horizon in the east than in the west, you can substitute "easternmost" for "westernmost" in the above.
Once you have done this, go to any convenient satellite, loosen the support that holds the feedhorn out from the dish (if you can - some dishes have no way to do this) and push the feedhorn in and out a little without rotating it any. Even a half inch in or out can make a pretty big difference in signal strength.
For your skew, if your receiver doesn't have continuous skew scanning (-90 to +90 on many receivers) then pick either polarity, loosen the setscrew in the scaler ring on the feedhorn, and rotate the feedhorn until you get the best signal on that polarity. Be careful to keep the feedhorn the same distance from the dish and pointed in the same direction while you do this. When you find the best spot, use a small marker or pencil to place a mark on the scaler ring and the feedhorn, so you can return to this sport easily. I'd personally do this while looking at your due south satellite, but that's just me. Note that if your feedhorn mount allows rotation of the feedhorn (such as on a "buttonhook" mount), it may be easier to do the skew adjustment there, but you'll still have to loosen the setscrew on the scaler ring for the next step.
While you have the setscrew loosened, you could (after you find the proper rotational position) try sliding the feedhorn in or out of the scaler ring a little. I've seen a little as a quarter inch make a huge difference here, especially if you were unable to change the distance of LNB to dish.
Also try to make sure that the feedhorn is pointed at the exact center of the dish. There are ways to do this that involve pieces of mirrored tape and and a flashlight at night, and ways that involve sticking mirrors on the dish itself. I usually use the "eyeball and hope" method.
But if you've tried everything else and the signal strength is still low, that would be one place to check.
The one thing you will be amazed at is how small, seemingly insignificant changes (particularly in distance of feedhorn to dish) can get or lose you ten or twenty points in signal strength. It's real easy to see this with a digital receiver.
I know you probably know most of this already, but having had a big old C-band dish since the mid-90's, I had to learn the hard way how to peak it for best signal strength, so I'm trying to give you my accumulated experience in a few paragraphs. It takes time to do it right, particularly when trying to track the arc, but it's well worth the effort.
