That means that you either knit or purl too loosely. Figure out which one it is bu working a swatch, one of purled garter stitch (purling all rows) and one of regular garter stitch (knitting all rows), using the same yarn and needles. Measure your gauge and that will tell you which one you do more loosely.
Once you have that figured out, use a smaller sized needle to work the too-loose rows. If you're working in the round, it won't matter.
One of many knitting guys.
CONGRATULATIONS TO AMY AND SHELDON ON THE BIRTH OF THEIR DAUGHTER!
Are you knitting continental or English? I tried conti and simply couldn't get even tension, especially on the purls.
It does take time to get a feel for your tension while knitting. My first project looked terrible and was extremely uneven with regard to the tension. If you're just learning, cut yourself some slack. It'll come to you with practice.
What do you mean guys don't knit?
Linux: because a PC is a terrible thing to waste.
Perfection is overrated. Knitting is meant to relieve stress, not cause it. Relax and enjoy it.