The Guitar Wiring Blog is an old established site where I picked lots of diagram when I started modifying guitars.
You can use a DPDT-SW (Double Pole, Double Throw) in your guitar wiring in many ways. You can base many types of tone switches on this thing. You can use it as a pickup selector. It can change the coils in your guitar pickups (series / parallel, split humbuckers, reverse phase, on-off, etc.). Creating a switchable signal bypass or loop is also a good part.
This diagram shows you DPDT connections in some popular examples:
As you can see, push-pull pots also have a DPDT switch: ON-ON.
Versions with a toggle switch are the most popular. You can get them in many sizes and types (on-on, on-off-on, on-on-on). Some models are very robust.
Here are some examples of how I have used these things in my guitar wiring projects:
Direct-Through Strat Mod (Bypass)
On-board effects loop control
Custom wiring for Explorer, Flying V, ML, Razorback (Pot picker)
Dick Dale Stratocaster wiring (‘Bridge + Middle’ pickup activator)
George Lynch’s guitar pickup selector
Gibson Les Paul Jr and SG Jr Wiring Mod (Sound switch)
Altitude vent switch
Easy guitar wiring without pots (Phase sw, “on-off” recording selector)
A DPDT switch can go through part of a really handy guitar tone control. These with toggles are more robust and comfortable, but they cost an additional space in a guitar body. Push pulls are usually less convenient, but you don’t need any extra spots / holes to use them – you just have to swap them out with your old pots.