[apalrd]

The best tip is to use as little big wire as possible. For every motor controller, shorter means less resistance to that motor, but for the main battery cable, it affects the whole robot. So keep it short. Even if it means slightly worse routing to get a straighter line.

The main battery cable is the one wire that I never really constrain in any way. It moves point to point as efficiently as possible without getting too close to mechanical components. I never try to include it in wire bundles, as this wire tends to get hot (sometimes to the point of being slightly sticky) and a bundle of wires around it would let it get even hotter. As solid as it is, it tends to hold it's shape.

Battery to Main Breaker to PD Board layout and distances are critical to short cable runs. The battery includes a foot of wire, use it to your advantage to keep the main cable short. Draw a line (in your head) between the battery and PD board and put the main breaker on that line. Avoid the temptation to put the breaker feet away from that line 'for easy access', and find an area on or very close to the line which has sufficient access. You have to be able to get to it, but it does not have to be on the edge of the robot (in fact, I've seen side-mounted main breakers get hit during a match, and turn off).

As for termination, we've always used crimp connectors and dip soldered them. We use a large crimp press that we have access to. I can't help with any easier way to do this, but wrap the connection in electrical tape neatly.

#4 is even more unruly.