Teen Vogue's latest issue includes an interview with Willow Shields, Jennifer Lawrence, and a small Q&A with both Jennifer and Sam Claflin.
Willow on learning to identify with Prim:
"My sister, Autumn, and I are twins [...], Shooting a dramatic scene like the reaping, I imagine it happening to Autumn in real life. Having a sister is very helpful for this role."
On Mockingjay:
"What Prim has to do in Mockingjay will be a real challenge. But I love a challenge."
The article is definitely worth checking out for the banter between Jen and Sam:
Sam: I first bumped into you at stunt training. Your archery put me to shame. I was quite intimidated.
Jen: By the sight of my face!
Sam: Yeah, it really put me off. 
Image courtesy of QuarterQuell.org
Image courtesy of QuarterQuell.org
Image courtesy of QuarterQuell.org