This how to will help you add nicknames to your contact for Cortana to understand.
This how to will help you pin “Me” tile to home screen back if you accidentally unpinned it.
If you have recently upgraded your phone to a windows phone, then there are chances that you are not seeing the contacts which you stored in the SIM under the “people”.
Twitter contacts might not be people you know and that’s why you don’t see them in people, below is how you view twitter followers.
Windows phone allows you merge duplicate contacts because its a nightmare when you have the same contacts in different account and your phone shows them all.