Teleporting:
Teleport to someone: /tp [your username] [their username]
Accept a teleport: /tpaccept
Teleport someone to you: /tphere [their username] [your username]

Warps:
List of all warps: /warps
Warp to specific place: /warp [name of warp]

Mail:
Sent mail to someone: /mail send [their username] [mail message]
Read your mail: /mail read
Delete your mailbox: /mail clear

Land Claiming:
To start claiming some land: /kit claims
1. Right click in one corner of the area you want to claim with the golden shovel you are given
2. Right click in the opposite corner of the area you want to claim with the golden shovel
3. Hit the stick anywhere in the claim to see who owns it
For further instructions, watch from 3:10 to 15:00 of this video: www.youtube.com/watch?v=TLR4GrOiGOY

Player Shops:
To create a shop: /shopkeeper give
1. First decide if you want your shop to sell things, buy things or trade things by right clicking in the air.
2. Place down a chest. Put the objects you wish to sell, including extra stock, in the chest.
3. Right click with the villager spawn egg to connect it to that chest.
4. Click a block around the chest to put down a 'Shopkeeper'.
5. After you have placed the shopkeeper, shift and click the shopkeeper to edit things such as the name of the shop, how much to sell the items for in emeralds and other features. The system will guide you through the process as well!

Other helpful commands:
Free stuff: /kit daily, /kit tools
Toggle treecapitator on or off: /tc toggle true, /tc toggle false
After death return(keep inventory is ON): /back 
Message someone specific: /msg [their username] [your message to them]