I've read through the Tactics FAQ and watched the video, but I'm still failing miserably.  What kind of genes are better, what should I be looking out for? It always says skip reroll, is that normal or is my lineup bad? I'm not using any moves that say they forbid reroll. On that note, are things like fire attack and acid attack worth it? They have a lot of points but forbid reroll? I feel like I'm not getting this.

You're suppose to select which die to reroll. As for the others, I can't help you there, since I haven't been to the battlefield more then a couple of times (to see how it works).