Skarner early power comes mainly from his Crystals inside the jungle and the river. Capturing them whenever possible will slow his clearing speed.
Skarner power Crystals gives him a massive buff to movement and attack speed, always try to fight him away from them.
Without his Crystals, Skarner goes out of mana pretty fast. This is good way to punish him, and if you can also steal his blue buff, Skarner will struggle.
Skarner excels at locking someone down and then dragging them towards his team. An early QSS or Mikael's is a good tool to deny him this potential game winning combo.
Skarner will be looking to grab one of your carries and drag them towards his team, be ready to peel for them and CC Skarner when he comes in range.
Skarner will try to extend fights as long as possible, as he can absorb lots of damage thanks to his shield and healing. Short skirmishes are the best way to beat him.
Albeit being usually labeled as tank, once Skarner gets his Trinity Force, he can dish lots of damage if left unchecked for too long. Peel him off your carries to prevent them from dying.
Once Skarner hits level 6 he can lock someone down for 3 seconds by using his . To prevent this dodge, his or have ready your QSS.
When Skarner activates Righteous Glory in conjunction with his and Predator, he gets a massive movement speed buff that he will try to use to get to your backline. Kite him and always try to have a a frontline standing in front of him to prevent the slow wave hitting everyone