Your jungler is your friend.
Being a good player overall in the game means understanding the roles of every player on your team. It's not easy to jungle, jungle is the hardest and more important role in the game. If a jungler dies to your mid, don't blame him, blame yourself for not being able to kill the other mid fast enough. If a jungler gets caught counter-jungling, blame yourself for not following and fighting with him. AP Mid is the role that requires lots of attention to your teammates and the enemy team. Always have high MAP AWARENESS to know where the enemy jungler and what your jungler is doing. If your jungler is invading their blue, go help him if he needs it. Remember, your jungler is the one giving you blues to make your lane easier, plus mid lane is the easiest for him to gank, so be nice. Having a positive attitude wins games.
Jungler Paths
You must know the general location of where the enemy jungler is at all times. This way, you will be able to zone your enemy while still saying safe. For example, if you know the enemy is at their red, shift to the opposite side of it because you know you'll be able to have an escape route if they come to gank.
Wraith Camps
Take wraith camps if you're pushing your lane will help bring up your money income. If you're playing a character who farms easily such as Orianna, counter-jungle the enemy by taking his wraiths and you can take your own wraith camp too if your jungler doesn't mind it, then you'd have op farm.
Ward Placements
The support is not the only one on the team who needs to buy wards. Vision helps out the team A LOT. Every time you recall to base as mid, try to spend all your money whether it's for getting a few extra pots or wards.