just all garder stitch does not form a pretty edge.
You have various options.
you can do as trvvn5 said.
You can purl the last stitch (or the first one) of every row.
you can lift the 1st stitch off with wrapping the yarn around...
the problem of a "regual" first stitch is that you knit the same stitch tiwce in a row. so there is more string flexibility and often one of the stitches (usually the bottom one), gets contorted and pulled up.
I personally prefer the "purl the last stitch" method. Nice egde and you can not forget which is your last stitch.
enjoy your project!