I have never starched fabric when making a quilt top. I honestly did not know about that trick until I joined this board and have yet to try it. I understand it can help if you have diagonal cuts. I always wash my fabrics to remove the sizing, before cutting, because I prefer working with soft, pliable cloth.
But I have found that if you are sewing a diagonal cut to a straight cut, put the diagonal on the bottom and it will not stretch as much.