Tips for beginner Mids?

Look up builds on Mobafire for the champion you're playing. I'd recommend Annie or Malzahar. Focus on minions for now. Once you've practiced a bit i'd say after you manage to average at 65-80 cs at 10 minutes try using the map more and buy some vision wards (Theese will be very useful once you get the basics down)

Also a good tip is to just start the game out by doing /mute all since this game isn't very noob friendly, or just friendly in general.