That's a good question, but I don't think there's an answer. I believe the tension at which you knit is just there. You noticed a change in tension because you started out brand new and as you got better, you had better control and were probably more relaxed. I think it evolves for each person.
You can consciously control how tight or loose you knit, but it's not a good idea to try, since it's too hard to be consistent that way. I think it just comes with practice.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry