Methods for forming proppant pillars in a formation during formation fracturing include include periods of pumping a first fracturing fluid including a proppant and an aggregating composition including a reaction product of a phosphate compound or a plurality of phosphate and an amine, periods of pumping a second fracturing fluid excluding a proppant and an aggregating composition including a reaction product of a phosphate compound and periods of pumping a third fracturing fluid including an aggregating composition including a reaction product of a phosphate compound, where the pumping of the three fracturing fluids may be in any order and may involve continuous pumping, pulse pumping, or non-continuous pumping.