Sync contacts to iPad

I am a long-time Mac user, and have just bought my first iPad. I am trying to copy my Contacts from the iMac (Mountain Lion) to the iPad, and can't seem to find a way.

I have set up iCloud and enabled contacts on both iMac and iPad, and it syncs one-way: contacts from the iPad find their way to the iMac. But contacs from the iMac don't get to the iPad. There are 21 contacts in th iPad, and 116 in the iMac (including the 21). Why won't they go back, and what do I have to do?

I have also made a direct connection via USB and tried syncing via iTunes. But the contacts data doesn't appear anywhere and nothing I can find can make the copy/sync happen.

Of course I am new to both iPad and iCloud, and my difficulties are likely finger trouble, but any guidaance on how to get my contacts transferred would be welcome.

Thanks.