I'm having the same issue, only my desktop machine is an iMac. I have enabled sharing in my iTunes, and I have iTunes up and running on my iMac. My Apple ID is entered on my iPad. Both devices are connected to the same network. But, when I click the "More" button in my music app, "Shared" is not among the options. I see only Genres, Composers, and Podcasts.

I keep thinking I must be missing something obvious, but what?

I'm having the same issue, only my desktop machine is an iMac.

What worked for me was:
Under the "Advanced" menu in iTunes, there's a little item labelled "Turn On Home Sharing." Even though I had my Apple ID entered in Preferences, and the Sharing preference pane showed "Status: On," it didn't work until I found the item in the Advanced menu.