With the hand piecing, really there is no right or wrong. It doesn't matter if your stitches are big. My stitches aren't exactly small, but they are OK. I do however have a long history of doing cross stitches, so can sort of control my stitches, but you do get better as you go along.
As long as your pieces stay together and look OK, it should be alright. Is that sort of what you wanted to know?