Knitting Tightly / Loosely

[dagny]

I'm working on a scarf in the round with simple stockinette stitch. Everything is going great except that my knitting is not consistent. I can't seem to make all my stitches the 'same size,' ie, some rows look fatter / looser than others. Is this something that will just improve with time, or can I do something specific to manage the tension of the yarn better? I guess I've noticed that when I have the yarn pushed back away from the points of the needles it ends up being a looser row but it seems like to keep things the same I'm constantly having to push the yarn back and forth on the circular needles.

I may not be making any sense because it's 1:45am