I am nearing the end of my boat rewiring project. I tore into a 1974 Pearson 30. Half was the original wiring and the other half was a hodge-podge of AC and DC from the two PO's. I am very fortunate to have found a great marine electric shop down the road from me in Annapolis. The prices for supplies are really good, and the owner is always willing to help. I design and build manufacturing equipment for a living, so I too had experience with wiring. Here are the tips I learned the hard way or was lucky enough to have someone share with me.
1) Do not go cheap on wiring, connectors, or the distribution panel.
2) Always use marine grade tinned copper wire. Pure copper will corrode, trust me
3) If you need to splice a wire, use adhesive lined shrink tube. This will mimmick the insulation and protect against corrosion, and water intrusion.
4) Do not use any wires smaller than 18 AWG. ABYC found that anything smaller can fail due to vibrations. I found 14 AWG to work for 90% of all my wiring needs
5) If you can, place a small terminal strip near your fixtures (lights, fans, etce.) so you can easily swap them out later
6) Check out the Blue Sea DC Circut wizard to help you with wire sizing. There is a link on thier main web page.
7) Draw a schematic before you start wiring. This will help you remember everything as well as be a great reference for troubleshooting later.
8) Buy a decent set of wire strippers and crimpers. Your hands will appreciate it.
9) Do your best to not solder. Soldering reduces the flexibility of the wire and can cause the joint to fail from vibration over time.
10) The most important of all... KISS. Do not over complicate your systems (for instance, keep it at one inverter)
There are many more, but these are the big ones.