There are three sites you need to visit and study up on....
Delcity.net for tools for doing it right. Get at the minimum some ratcheting crimpers.
Blue Sea Systems, order a catalog for free, they make switches and panels and everything boating related, top notch stuff...The catalog has many tutorials and diagrams that will really help you out.
Best Boat Wire & Cable - Complete Marine Grade Wire, Cable and Electrical Parts Supplier has the wire and connectors and heatshrink, for the lowest prices, and they have exceptional service. I wouldn't go anywhere else. Remember, bus bars are your friend, and seal everything.
With these three links, you should be about straight. Also, I'd like to recommend the clear heat shrink, because then you can see if there's corrosion on a crimp or connector without having to disassemble it.
Good luck Ryan
Use marine gauge wire for everything, and adhesive lined heat shrink connectors.