Step 1: Go mid lane.
Step 2: Lock in Lux; probably the most free mid laner besides Yasuo, and easy to learn. If you get a ban, ban Xerath, Orianna, Ziggs, or Veigar because they will make your life horrible in lane.
Step 3: In-game, you'll want to E minion waves then auto attack to proc your passive; it's actually pretty easy to CS with this mechanic.
Step 4: To delete a champion: E-auto-Q-auto-ult-auto for maximum damage (270% AP!) Now, don't auto if it puts you in danger; the dmg is not worth it. You're fragile, so be careful! Abuse your range; you outrange most mages so spam your Q and E and only auto when you CS or the enemy is vulnerable (out of mana etc). Your ult has a LOW cooldown, you can have it up more than your lane opponent. But: ONLY ult when their passive is marked on the enemy because it will ignite it and deal extra damage. So slow with E, snare, and ult. You'll never miss because they're stuck, and if they still aren't dead you can just walk up and ignite or proc passive again since your ult adds the passive another time.
Step 5: Mute everyone, because mid lane doesn't need more communication than pings.
Step 6: Buy the tear of the goddess; you will NEVER run out of mana, and it's hidden-OP because it gives over 150AP when completed. Then go standard AP items; get 40% CDR.
Step 7: Win
Now I'm only B4 but I've tried this, and it works well. Spamming a more simple champion helps a lot; champs like riven, yasuo, lee sin, vayne etc are really technically complicated and you should avoid them.
Good luck!
And PS: NEVER EVER do the stuff on YT. Attack Speed jg thresh? Don't ever. The people who make the videos are gold or higher and know how to perform relatively well with them.