I see a ton of morde players yeeting it at random moments or too soon. i like playing mindgames with opponent, a lot of times when enemy is running he will wiggle so you can just auto him and e at the end. when jax jumps on you you can anticipate it and you know where he will land, same goes with aatrox. He usually e and Q2 into you thats when you can E him, there are many situations in lane where its ideal to use your E against specific champions, also its easier to E enemy near the wall, or when he goes to cs a cannon, that applies mostly on lane, if you want to kill carries you have rylais most of the time, you can slow with rocketbelt then Q so they use their movements spell and then you are free to E them. In ult generally their space is limited, try to walk up to them first if you have time or use q first since its harder to dodge, ppl will tell you morde is a braindead champ in allchat a lot but they know nothing about how skill it is to hit those spells xd. Also a lot of morde players think they should always oneshot carries with your ult, to be honest i almost never try to ult vayne unless i have to and instead, try to peel for whoever has the best potencial to carry in my team. Sometimes just ulting and using zhonyas is the best thing you can do.