I prefer the "50's Mod" over bright caps/treble bleed circuits. Installing a bright cap always sounds a little to edgey or crisp to me, although both Lindy Fralin and Kinman have come up with little R/C (resistor/capacitor) networks that sound smoother than a cap alone because the resistor is used to determine the amount of treble allowed to "bleed" across the volume pot. Without a resistor, the treble is like it is on "10" all the time, regardless of where the volume is set.
The 50's mod is simpler. The middle terminal of the tone control is usually connected to the same terminal of the volume pot that the pickup or output of the pickups selector switch is connected to. Move that connection to the middle termal (output) of the volume pot...if possible.
It's easy to do on Gibsons and Teles...harder to do on Strats. But Artie came up with a diagram of how to do it on Strats too.
Lew