There are a lot of products and methods out there. I've used Eastern Beaver PC-8 with excellent results and found the plug and play version for the Yamaha Super Ten to be very nice and simple to use. I've also run Fuzeblock units, used JohnR's methods and recently went with a
Healtech Thunderbox. The Thunderbox has no fuses, is all potted electronics and uses a clamp style design for the wire inputs, so strip a bit at the end of the wire and insert, flip the tab back down and you're done. No soldering, no crimping, no other connectors to fuss with and no tools to install or remove a farkle from the unit. Auto reset if it detects a short, if it happens again, it cuts it out of the system for safety. Small and easy to tuck away as well. I ordered direct from the manufacturer in Hungary and received it in only a few days. No customs fees/duty for motorcycle parts in the US, so no surprises on the cost, just the price I paid online for the unit and a flat $25 shipping charge.
You can opt for 4 or 8 circuit versions with a price difference. this is the 4 circuit version. Black wire is ground, green is 12v. White is an optional switched power connection that will shut everything down with the key. If you leave the white wire unconnected, the automatic cycle is default. The unit goes through a short learning cycle when first powered up and after that it knows when the engine is running and only powers your circuits when the engine is running, and powers everything down a few seconds after you shut the engine down. Since I sometimes desire to poke my GPS with the key on, engine off, I connected the white wire to a OE switched source.
The orange tabs lift up to allow wire insertion/removal.