Have you done any knitting at all yet? It's usually a good idea to do something like a scarf or a dishcloth for a first project. You can learn how to do the knit and purl stitches, learn what the stitches look like, practice ribbing, etc. Just get a feel for knitting and get comfortable with it.
There are no hard and fast rules though. Check out the patterns at these links and see if something strikes your fancy.
Knitting Pattern Central