Morrigan and Sten are both really hard to please. You basically want to give Sten gifts and wait until he approaches you. Morrigan will sometimes talk to you (don't talk to her in town, wait for camp or she gets snarly) but she's also easiest to raise by gifts first, then talk to her (save first so you can reload if you mess up), and then she goes waaaaaay up when you complete her quest.