Oliver's a more light-hearted and flirty person so those kind of options will point you towards him, but you also have to recognize that he's serious about his work. Being proud of starring in the movie, appreciating or being interested in his writing...those will get him to start considering Christian a little more deeply, which is what starts the route.
Thank you very much for your help! I have now completed the game, and I loved it very much. This nanoreno entry is awesome, you really outdid yourselves with WWLOS. :)
Do you have any hints on how to get onto Rainiers route? I love the game :3 but rainiers not giving me the time of day xD
Rainier hates show-offs and shallowness, and he takes his work /very/ seriously. If you make choices that show that Christian is more down-to-earth and also takes acting seriously, you should be good!