Send Elixir Golem with Battle Healer, Electro Dragon and Night Witch to build constant pressure. It's cheap, so you can send it often. Remember that it gives your opponent elixir, so the push has to deal damage.
Tips
Paired with Battle Healer, Elixir Golem survives for a long time.
Your opponent gains elixir as they kill it, so don't send it unsupported.
Using Elixir Golem to kite on defense is usually a bad idea.