I’m sorry, but it... really hurts to see. You have a lot to improve, start with the small stuff first:

• Attack move. Don’t just stand still and auto attack. You can auto then move to a different spot for a “smoother” feel (I’m also bad at this, so it’s hard to explain) and an easier time dodging skillshots. People normally do it with the A button (I think, again I’m also pretty bad at this), personally I just click around faster.
  
• Learn to last hit. This process is a long one, but the general idea is adjusting the timing to hit the creeps at the right time. Also, melees die to turret in 3 hits, casters die in 2, one auto from an AD champ can kill a melee after 2 hits, and caster after 1, so if your lane gets pushed it’s a way to time correctly.
  
• Set your spells to smart cast. If you’re used to what each skills do then you can just aim them in smart cast by hovering the cursor in the general direction you want, it saves a lot of time then trying to adjust the aim with normal cast (there are some exceptions to this, such as Viktor’s E or Rumble’s R, but that’s a story for another time)
  

Of course there are a lot more, but I think those are the most basic mechanics to learn for someone new at League. (And if you’re just trolling with the vid then well played good sir)