Sneak is key. I actually find rogues to be much more viable than rangers early game. Rogues' damage picks up much more quickly. If you want your rogue to be safe, pick a target behind whom you will be out of sight (e.g. an archer at the back of a fight), and save a few action points to hide at the end of each turn). Works a lot better with glass cannon... so that those few action points aren't your whole turn.
