Stockinette problems

I’ve been knitting for 3 years now and wish to advance beyond scarves. My first big project is a sleevless summer sweater hopefully to be done by summer 2006. but my stockinette stitch on that project went wonkie, so I returned to a basic striped stockinette scarf; same problem. My first stitches on the (RS) are high and the last sticthes seem to dip making the project lopsided what am I doing wrong. Itry to keep my tension consistant but it isn’t working. THANKS :??

A few things could be going on.
Firstly, most people’s purl stitches are looser than their knit stitches because of the way the yarn is wrapped. This may be causing your biasing. You might find that some blocking fixes that up without a problem.
Try knitting a swatch in stockinette and either wet or steam blocking it. If it looks ok after blocking, you are fine. (You should do this anyway if you are making a garment you hope to wash)

Secondly, stockinette tends to have pretty ugly edges anyway. Many knitters prefer to work a selvage stitch to clean those edges up. There are two that I know of that you might want to try.

One option is to knit the first and last stitch of every row so that there is a one stitch garter stitch running up both sides of the fabric. Another option is to slip the first stitch of every row. This makes a very nice chain up the edge of the piece. I personally prefer this one and find myself doing it automatically, but it’s purely preference.