On start and early game u must buying wards, becouse you are easy to gang. Your second must is farming, without this mordekaiser suck. When you have

revolwer hextech

[*] you can spamming skills, on early only last hit.

On team work you tanking and dealing great magic damage tou go first or second and using all skills
when enemies focus u oyu using your summoner spells and escape. Your ulti skill using only to kill, becouse it,s great to have some kills- what u need.

You using w for armor, q for speed and e for desling dmg when you going. You harras with q and e.