Elizabeth: Most that I know go by their full names, but when I do hear nicknames, Ellie, Ella, & Beth seem to be the most common. This is one of my personal faves, but sp. Elisabeth, and I'd be inclined to use the full name, but the occassional Ellie when she's younger would be cute :)
Katharine/Katherine/Kathryn/Catherine: I do know a few that go by their full names, but Katie (when she's younger) & Kate (when she's older) seem to be more common. This is another name that I like, sp. Kathryn, and again, I'd be inclined to use the full name, but the occassional Kate or Katie would be fine :)
Julia: Every Julia that I know goes by her full name, although I'd want to go by Julie, since I prefer it over Julia. I've also heard Jules as a NN.
Julianna: Most, again, go by their full names, but I wouldn't be surprised that some go by Julia, Julie, Jules, or Anna.
Olivia: I think this name does typically stay in full, but there are a few who go by Liv or Livvie.
Jennifer Nicole
Loving the Names:
Ariella Kathryn, Carrie Marie, Elisabeth Ava, Faith Alexandra, Michaela Reese, Sadie Elisabeth
Cade Preston, Deacon James, Grant William, Jude Hamilton, Roman Spencer