A good power source for your amplifier is one of the most important elements for good sound reinforcement. Especially in the bass response and peeks. To add extra PUNCH to your sound power capacitors can aid in this by having a hugh amount of voltage stored up that will discharge any time the voltage from the battery drops below stored voltage.
You will want to run your red wire from the battery to your amplifier. There are a few places to run your wiring through the vehicle so as not to be disturbed.
One of the ways is really running under the vehicle inside of neoprene hose, PVC or conduit. You must be careful where you run this wire if you plan to do a outside run. Your vehicle may be an off road-er at times so try to run the wire inside a frame or at least along it so it can't get caught on anything rubbing along the bottom of the vehicle.
Try not to drill holes in the frame, most of the time you can find places to attach to already there. Holes in the frame could cause cracks to form over time. If you have to drill a hole, drill it centered of the mass.
Where you decide to come up into the vehicle be sure to check for wires that you may drill into. Use a grommet to insulate the drill hole from the wire. You may find rubber inserts in trucks that you can punch a hole in as well.
Always use a fuse on the red wire real close to the battery and wait to put the fuse in as the last step of the install. If any short happens to the wire any where along its length the fuse will blow. It is best to solder all connections.
If you know how to solder you can skip this section. For doing solder jobs with wiring, you will need a 30 watt iron or higher. You need rosin core solder not acid core! I will use the fuse receptacle as an example of a wire to wire solder job. After you strip the wire back, carefully separate the strands by lightly pushing on the end of the wire and twisting back and forth lightly! Then insert the wires together on center till it stops. Now squeeze and twist them lightly together. I use a plate to solder on. Put the wire and fuse receptacle on the plate and heat the center. Start rubbing the solder on the bottom side of the iron and on top of the wire, so you will be rubbing along the point of contact of the iron and the wire. Now we will solder the connector for the battery to the fuse receptacle. Twist the wire good then crimp the connect loosely. Now place these on the plate and let's heat the crimped part of the connector and put the solder on point of contact first then point of wire to connector contact until it flows out the other end.
You can also run the power wiring under panels, tracks, and carpet. But make sure your wires aren't running where a screw will go through them and cause a short. Never run power wire on the same side as the RCA wire. DC power wiring can cause induced signals to be applied to the signal as noise, pops, clicks, or alternator noise
Also plan to ground all additional components other than the head unit to the same point. This will prevent ground loop oscillations from presenting themselves.
If possible, use a screw or nut that's already in the vehicle. Unscrew it and take a scrapper or sand paper and clean paint and other things from the metal tell it is nice and shinny.
Don't forget to run the remote wire with the power wiring. It connects to the blue wire on most head units. Refer to your head units instructions for which wire to use to remotely turn your amplifier off and on via your head unit. I use crimp type closed end terminals to connect smaller wiring to the head unit, amplifier, EQ., or electronic crossover, etc.