YES this is my time to shine *-*
Item: Clothes. Lots and lots of clothes.
Reason: A girl can never have too many clothes

Hyerim's style is usually just a t-shirt or an oversized top and shorts or jeans, sometimes accompanied with a cap or a hoodie. She's not really girly, so I don't think we should give her dresses / skirt or too much pink or red. Also, it can't be difficult to wash, or contain sparkles.
Link / Picture: Item: Shoes
Reason: Same as above ~ Eunji seems to be fond of heels (because she's short keke

), but the ones that are like sneakers with stiletto heels. I think I've seen her with boots too, but I can't seem to find the picture
Link / Picture: 1 2 3 Item: Accessories
Reason: Tbh, I haven't really seen Hyerim wearing much accessories before. She's not much to accessorize, so I'll just keep this to a few hair accessories and bracelets.
Link / Picture: 1 2 3 4 5 Item: Earphones
Reason: She's a huge fan of music, so we should get her earphones. She probably has her own pair, but earphones can spoil easily sometimes ^^
Link / Picture: 1 I can't think of any personal gifts now, so I can only give you the fashion items that I think she'll like T_T I'll add more when I think of them.
Note; Forever 21's site is kinda ~loopy~ and it'll claim to be under maintainence, so you'll have to click on the link twice maybe before you can access it. But it's my favorite place to shop, so I'd really recommend their items ^^