Target Champions Only setting
Hotkeys -> Abilities And Summoner Spells -> Target Champions Only
Use this setting. I have it bound to the tilde key on my keyboard, but you can use any key you find comfortable to use in the heat of a fight.
Doing this will make you unable to target enemy minions or towers when you hover your mouse over them. But you will have to HOLD your bound key for it to take effect. If you want, you can make it a toggle, meaning if you click once, you will not be able to target anything but champions until you click it again.
Game -> Treat “Target Champions Only” as a toggle”
Setting up default item positions
When you buy your items, they appear in your inventory in order you bought them in. Problem is, a lot of players are used to having health potion, zhonyas or other active items in certain inventory places. This tip will automatically put your pre-set items into the correct slots.
Follow this short video-guide
From now on, every time you buy the selected item, it will go directly in your selected spot in the inventory.
Do this for potions wards, any item you buy. This will not only save you time while shopping, but will also save you from accidentally having your item in the wrong spot when you most need it.
A few Settings you should always be using if you truly want to reach your full potential
1.Enable Quick-Cast for your abilities
There are only a few circumstances when you want to use normal casts, but for the most part, if you really want to reach the highest skill level, you will have to learn to use Quick Cast.
2.Maximise your minimap scale
Map awareness is one of the most important things in the game. You have to have the biggest minimap available. Create a habit of checking the minimap every few seconds. Even before making plays or starting a fight, just to have an idea what the state of the map is. If you constantly check the map, you will see when an enemy jungler appears on the other side of the map, allowing you to play more aggressively. You will also notice when other laners leave their lane to roam. It is one of the most important skills to have as a player.