Command+,

Open Contacts Preferences

Command+N

Create A Card for New Contact

Command+Shift+N

Create a New Group/Folder

Command+Option+N

Create a New Smart Group

Command+O

Import Contacts

Command+P

Print Contacts

Command+L

Edit Current Contacts

Command+S

Save Changes in Contacts

Command+1

Show/Hide Contacts

Command+2

View a list and a card

Command+]

Go to Next Card

Command+[

Go to Previous Card

Command+Option+L

Show/Hide Last Import

Command+Shift+L

Merge/Link Selected Cards

Command+I

Open A Card in New Window

Command+Option+I

Choose A Custom Image for A Contact

Command+\

Make A Card as A Company or A Person