Once you have built the pot as far as it feels safe to do so, cover it loosely with plastic. You can continue to work on the pot after it has stiffened a bit. To keep working on clay that is too soft, especially over open spans, will eventually lead to the pot collapsing.
The plastic covering will allow the clay to dry slowly. This reduces the possibility of cracking. If the humidity is high and there is a possibility of condensation gathering inside the plastic, add a layer of paper towels or newspaper in between the pot and the plastic.
You do want the last one to two coil layers to still be soft and workable, so that later additions will adhere properly. If it will be several hours before you can return to the pot to work on it, place strips of damp paper towels over the upper layers before covering with plastic.
Note that in our example I have replaced the sponge in the longest span with a column made from the same clay body as the pot. This span was just a bit too long for me to comfortably leave it completely unsupported. The clay column was allowed to remain in place throughout the pot's firing and glazing.