Yes, I know heimer is generally considered a bad champion, but after just trying him out in unranked I feel theirs some serious power hiding here.

I had his turrets doing(combined) 190-200 damage PER shot. Shooting twice a second..that damage is ridiculous.

I want to learn to play this champion a bit more seriously. Any tips?

Max w first. Play the game at a slow pace. Be very patient and cast w any time the enemy has only two creeps remaining. Also, avoid farming with your cannons, he is good at last hitting with his high projectile speed.

Good luck.

Play someone else.

Start with W, then Q. Put 1 point into E when you can to protect from ganks with the stun. Always level R>W>Q>E. His poke with rockets is amazing so get a hit with it whenever you can. Place turrets on opposite sides of the lane so an aoe attack can''t take out both at once. E reveals through the fog of war, so if someone flashes over a wall throw E then W right after. R is situational. Use it if you have to recall and keep your turrets up for farm, in team fights for the 5 rockets, or to save yourself from a gank. If you do get ganked and flash is down, don't run. You're slow as hell. Hide between your turrets to keep the damage up.

Bam. You learned everything about heimerdinger in 30 seconds.