Making stitches at the tips results in tighter stitches. You have to find a position that's in between. The way you hold your yarn is a major part in what sort of tension you get. I thread mine through my fingers, no finger wraps, and find that it's tighter when the yarn is close to my hand, and looser when it's toward my fingertips.
It is a matter of practice; blocking or washing your piece when done helps even out the stitches for now.