Improving the rolls
PCs cannot Aid each other on either the +Fortunes roll or on rolls to generate Surplus. The move assumes that everyone is doing their part already.
PCs can Bolster for a coming season and spend the Preparation on the roll(s), but doing so should requiring a significant sacrifice to the gods (like 1 Surplus at least), and/or having the village Pull Together to make special preparations.
Handle other moves on a case-by-case basis, based on the fiction and what the whole group feels is right and fair.