Points to be Consider while you do the building foundation,

Step 1 : Make sure you do trail pit to know the your soil strata, before start of actual footing, this will give you fair idea where you suppose to place your foundation.

Step 2 : Consult you structural engineer about the soil condition, & ask him to design as per the site condition.

Step 3 : Ensure the excavation is done manually without disturbing hard strata, & the bottom and side are clean and dry.

Step 4 : Use Concrete mixture machine for laying of PCC to ensure right mix & Uniform, Ensure right thickness of the PCC.

Step 5 : Place the reinforcement with adequate cover at the bottom and sides,

Step 6 : Prefer to go for RMC from plant, therefore the right design mix and quality of Concrete ensured.

Step 7 : Do back filling after the adequate curing for the footing concrete. Ensure good consolidation of footing pits.