Most important bit of advice for any camino- travel light! I recommend under ten pounds. You don’t need 5 pairs of socks or 6 thongs. An extra pair of boots can weigh 2 pounds, but perhaps no one will steal your everyday ones. A long sleeve fleecey and a short sleeve are enough. An Altus Poncho can keep you dry, and warm. A sleeping bag liner is enough as most alberiques have blankets(from May-September). Collapsible light poles are great as you can hide them in your pack at night.
In most alberiques your boots are left at the door or just inside. I would have a plastic bag so that I could sneak my boots in to place under my bed. At first I would just remove my inserts but later I took the whole pair! Sunscreen and a hat are musts. A bag for treats along the way is necessary. I brought fibre bars, Holy Crap, a Spork and small containers for chocolate and nuts.