Identify the molecule or ion with possible electron delocalization
Draw the correct Lewis structure first
Locate π bonds, lone pairs, and formal charges that can move
Keep the atom positions fixed
Move only electrons, not atoms
Use curved arrows to show electron movement
Form new π bonds or lone pairs where appropriate
Ensure the total number of valence electrons stays the same
Check that each structure has a valid octet when possible
Recalculate formal charges for each structure
Minimize charge separation when possible
Draw all valid resonance structures
Connect resonance structures with double-headed arrows
Do not use equilibrium arrows
Choose the most stable resonance contributor if needed