Don't die early, or at all if you can help it. Get a couple of points into (R) Phoenix Stance and build your core items to burn through any enemy melee champions. Your early damage is high, but your survivability is not. That comes at around the 10 minute mark. Just expect your spike to take them by surprise as your 1st and 3rd hits from Phoenix stance deal 200+ magic damage, and the Liandry's burns them for 1.5% max HP every second you have Phoneix Stance activated near them.

As they try to escape, stick onto them easily with Phase Rush. Even after they've bought some movespeed items you were just waiting to get Rylai's to stay on them even more than before.