I’m not sure about your exact problem, but if you are getting a big, loopy looking stitch at the end of your row/beginning of the next row, there are a couple of things you can try.
One solution is to slip the first stitch of each row (slip it from the left needle to the right needle without knitting it), then start your knitting (or purling) with the second stitch in the row.
Another solution is to knit (or purl) the first stitch of each row, but make sure you pull up any slack in the yarn when you insert the needle for the second stitch.
Each method gives you a specific look to your edge, so you can play with them and pick the one you like the best.
If you think your problem is with the last stitch in each row, make sure you knit (or purl) it just the same as you knit (or purled) the second-to-last stitch in each row. Another thing you might watch for is that in flipping the work you haven’t inadvertently pulled the last stitch (which becomes the first stitch after you flip it) upside-down. After you flip the work, make sure everything is hanging vertically, that your working yarn is trailing off the back if you are knitting, or off the front if you are purling…