Position 1. Filters
As auto wahs, envelope followers, and other dynamically controlled filter effects respond to your attack, you don’t want to limit dynamics with compressors and/or distortion pedals that reduce dynamicrange. Most players also put wah pedals first in the signal chain—mostly to come before distortion effects—however Tom Morello is a notable exception.
Position 2. Compressors
Compressors can raise the noise level of everything that comes before them, so they should come as close to the beginning of the chain as possible.
Position 3. Distortion/ Overdrive
Distortion and overdrive pedals prefer to see an unmodulated signal, and the harmonics generated by a distortion device bring richness to any chorus, phasing, or flanging effects that follow.
Position 4. Modulation
Tremolo, chorus, phaser, and flanger pedals fit nicely here, due to the aforementioned interaction with distortion boxes.
Position 5. Volume Pedal
In this position, the volume pedal allows you to maintain a consistent signal from your guitar to your distortion devices, and get full shred at low volume. However, you’ll likely want to place delay and reverb effects after the volume pedal to ensure their tails continue to decay after the volume is cut.
Position 6. Delay and Reverb
These effects come last in the chain—usually delay, and then reverb—because placing them before distortion pedals can trigger a jump in the ambient effect level whenever extra gain is engaged.