Well, actual recognition, i.e. membership status in the UN, will not happen, as the US has promised to veto the application in the Security Council.
Instead, the Palestinians will probably opt to apply for an upgraded observer status in the General Assembly, from non-state observer through the PLO (which they gained in 1974) to state observer. They will most likely get this, but it will mean very little.
The only potential real outcome is that the International Criminal Court (ICC) has indicated that they might allow Palestine to become members there if their status is upgraded. And then they can theoretically accuse Israeli officials for the building of settlements on the West Bank.
This, in turn, will probably have very little effect, as Israel is not a member of the ICC and does not recognize its jurisdiction over Israeli citizens. It might, however, bar the accused Israelis from traveling to countries which do recognize the jurisdiction of the ICC, given that an international arrest order is issued from the ICC.