Hi. Can anyone explain why my front cross stitches are nice and uniform, and my back cross are loose. It definitely is a knit stitch going diagonal but not as neat as front. I feel I am keeping yarn tension even. ? ? ?

Are these front and back twist sts? You may be pulling more on the front st when you twist one way than the other or you may be pulling more yarn through the st in one twist than the other. Another way to do these sts is to reverse the order of the sts on the needle so that the second and first sts exchange places before you work either stitch. Washing and blocking may also help even these out.

What size needles are you using and what kind of yarn? Are you following a pattern or just practicing? If you have a link it would help us.