lol...well i am certainly NOT much more experienced but this one i do know i think
Susie is right about slowing down. we get so excited about "getting it" that we move too fast and things start going wonky.
I find usually the issue is when you start the new row. You have to make sure you are bringing the yarn around back of the needle and not up over the needle. When you first turn your work the yarn is likely going to be hanging down in front. If you bring the yarn up and over to begin working it will look like there is another stitch that needs to be worked. If you play with the yarn a bit you will see what i am talking about. Make sure that you bring it under and behind the needle and not up and over the needle.
this is assuming you are doing garter stitch (knitting every row) too. If you are purling when you turn your work you need to make sure your work is down in front when you start. never bring the work up over the needle unless you are actually trying to create the extra stitch (yarn over). If you are knitting and purling in the same row make sure the yarn comes between
the needles and not over them.
the best way to combat it is to count stitches on your rows every time until you are use to what you are doing.