It sounds like you're slipping one, making one. Which is you slip a loop from one needle to the other, then you knit in the space between the stitches. What that will do is nearly double the size of your work every row, and create huge gaps.
What your teacher wants is 7" worth of just knit stitch, yes? So you get very very very comfortable with doing knit stitch?
I have to say I'm a bit surprised that she's having you do it only 4 stitches wide. What that means is that you'll be doing a lot of turning your work, and it's going to be a lot easier for the work to slip off your needles because there aren't other stitches to help hold the stitches back. I'm much more likely to drop the first or last two stitches in a row, and that's all you have! Plus the first and last stitch of each row (so half your stitches) are frequently a bit funny looking.
Definitely try a washcloth, like 20 stitches by 20 rows. That'll get you more comfortable with how the stitches are actually formed into row after row of loops.
And I'd use continental. Since you're also learning crochet it'll be a lot easier for you since you're already getting used to holding your yarn constantly in your left hand. Plus, English knitting is soooo slow. The only people have any speed with English-style knitting are those who've been using it for years and they'd be faster than you anyway.www.knittinghelp.com
as recommended above. Specifically after you've done your cast-on, watch the "knit" video. Pay attention to where she's holding her yarn before the stitch, and where she's placing her needle to make the stitch, and the point where the loop from the previous row leaves the non-working needle.