In any case, preparation for wet and rainy weather is always to be considered. During Easter periods you should be aware that there are always more pilgrims in Santiago de Compostela and all religious sites. Try to define well the distance to be covered each day, taking into account the difficulty of the stages, where you intend to sleep and where you intend to get food.
Following the way is always a surprise, but it is important to take care of basic aspects of the pilgrimage (see indications on this website) to allow surprises to be as positive as possible. You must bring with you a legal personal identification document (citizen card in the European Union), European health card, bank debit or visa card. These documents should be kept in plastic bags, to prevent them from getting wet and damaged.
Don't forget your credential, which is your passport that proves you have completed the way, at least the last 100 km (on foot) or 200 Kms (by bicycle). The credential is stamped along the way in the places where you sleep, such as hostels, but also in monasteries and churches, parish councils and even in cafés.