Here are just a few, not in order of importance:
Take the train from Bayonne to SJPP,
Attend the Pilgrim Mass in Roncesvalles,
Stay (at least once) in the old albergue in San Juan de Ortega,
Do visit the old church in Rabanal del Camino and stay for Vespers and Gregorian Chants,
Try to pick up a bit of garbage along the way, and definitely don't leave any of your own laying around,
Be grateful; don't complain,
Have a supply of chocolate with you, and share it it others,
Make sure the boots you put on in the morning are your own and not someone else's; ditto for walking poles, and taking clothes off the line,
Leave a donation at bars and cafés if you just stop to use their facilities,
Greet non-peregrinos you pass along the way with a "Buenos Días."
Stop for lots of cafés con leche,
Enjoy your fellow pilgrims.
Buen Camino.