How can I sync contacts?

From the Home screen, touch the Menu Key > Settings.
Touch Accounts & sync.

From the Home screen, touch the Contacts Key in the Quick Keys bar.
Touch the Menu Key > More > Accounts.
Touch the account you want to sync.
Touch Sync Contacts.

[Note]

Each account has different sync timing.

Google Accounts allow you to select (with checkmarks) whether or not you want automatic synchronization. You can also touch the Menu Key and touch Sync now to manually synchronize data.