I've been doing this with a sweater. I purl all the way across on the ws, then I turn and slip the first 3 stitches and finish knitting the row. This way the stitches get knit every other round, and they always end up on the same side.
For garter, you'd have to designate a right and wrong side, and do the i-cord slipping on the right side.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry