If you're working in stockinette--knit one row, purl one row, you're working a wrong side row when the purl bumps are facing you.
If you're working in garter stitch, both sides look the same and front/back really doesn't matter until you start shaping, if that's part of the pattern.
For garter, you can just pick a side to be the right side if you like--a pin, or piece of yarn tied on there.
"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