Depends on how much power you want and where.
For a two-pin (SAE) connector, I just hook a fused wire to the battery and run it out the side. Use a zip tie to fix it to the frame if you want.
If you would rather run 3-5 outlets, then use a fused power distribution box so you don't have to hook up a bunch of connections to the battery. There are things like the PDM60, that's the one that popped into my mind, but it may be more expensive and complex than you want or need.