I learned from car audio magazines and the write-ups in them over the years.
You might want to try the12volt.com, just be forewarned, on ANY site there are more people that do it wrong than right, and you have to weed out the bad wiring information from the good.
The key points are:
Keep signal and power wires as far apart as physically possible for the longest distance in the run(s). At some point, near the amp they will have to come together, or close, so that they all connect to the amp.
In most cars running the power wire down the driver side is best due to most cars having most of thier front to rear runs of the OEM harnesses down this side, or at least the majority, J-body included.
Running speaker wire beside power wire is fine, there is no effect from running speaker wire with power wire, since the power is DC and the speaker signal is AC, there is no cross effect.
Proper grommet through the firewall is paramount, this is a safety issue, not a beauty issue.
On GMs (other than very old and some very new models) there is a battery terminal adaptor that is required. Don't let your friend say "Oh just placing the wire connector between the battery terminal and battery is fine", it is NOT, this causes added resistance between the battery and the vehicle electrical system that will cause problems, if not soon, then at some point.
Proper ground for the amps is also paramount, I use a heavy piece of metal, usually an area where a spot weld is, because this is where the metal will be doubled up, and give the highest concetration of metal to provide a good ground path. NEVER use the seat or seat belt stud or bolt for this, this will provide a mediocure ground at best and will cause problems, same goes for that bolt at the very back of the trunk holding the bumper or bumper cover on, and that plastic clip that holds the netting, yeah that's not a good grounding point, don't laugh, I see this on a regular basis.
Running the remote wire with the RCAs is fine, I've installed thousands of systems this way and not one of them has had induced noise from this, the current is so low that it does not create a large enough magnetic feild to cause problems with the signal. This is also a nice clean way to run the wires.
Run the wires UNDER the carpet, it doesn't take long to remove the sill panels, and fold the carpet back to lay the wires in there. This looks good and keeps them protected from people stepping on the sill panel. Just sliding the wire under the sill panel, whihc I see far too often can cause the wires to get pinched by the supports that are molded into the sill panels, and cause problems.
I'm sure there's more, but those are the important ones that come to mind.