easiest resist is starch.

all resists will allow some dye seepage, so do a nifty test first.

Hey, luxx.
 we just soak our whites the night before. (resist dyeing, already stitched, but we band any areas we want after its all soaked, so socks would be dumped in the water with no prep whatsoever.)
 the only real thinking ahead is to let our 3/4 full 5 gal bucket of water sit out 24 hrs to dechlorinate.

when you say new, do you mean unwashed? maybe there is sizing on the fibers.
I know mass market T-shirts have to be soaked before dyeing.

also the colors you see are how the dye breaks, That sepia brown is pretty common.