Need some Kassidin Mid tips

I have recently been trying to pick up Kass in Mid but I'm usually struggling to go through the laning phase smoothly, for I rarely out CS my opponent and struggle at preventing them from roaming. What should I be doing before 6 and after 6? What are some good items on him, I usually get RoA, Abyssel, Sorc shoes, LB/IG, Sometimes deadman's if they have a lot of AD but usually I am not sure what to get after that. Also how do I deal with Syndra and Zed at mid, I rarely ever get through lane phase without dying to them. Also what are the idea runes and masteries to use on him?