Quite often, wiring up your guitar can be a bit frustrating. The best approach is to use a wiring diagram or schematic so that you have a clear idea of what goes where. Here are some very helpful links for Guitar Wiring / Schematics Diagrams.
Stratocaster
Telecaster
Les Paul
General
GuitarElectronics.com Guitar & Bass Guitar Wiring Diagrams & Repair Resources
Understanding Guitar Wiring at Stewart-MacDonald
Guitar Pickup Wiring Made Easy
Guitar Wiring – Humbucking Pickups, Modifications, Guitar Effects Schematics