Sibling Rivalry - Ignore or Get Involved?

My youngest daughter was inconsolable last night. She was upset because she thinks that she is ‘useless’. It broke my heart.

She isn’t, far from it, but her hormones are kicking in and she has started comparing herself to her sister. Tallulah is naturally academic and studious, and when she puts her mind to something she becomes obsessive about it. Her current obsessions are the piano and ‘Cubing’ (Rubiks cube to me and you). She’s watched Youtube videos on both and then taught herself. When she comes home from school she completes her homework and then sits on the keyboard until bedtime. Of course as proud parents we look on and encourage her and we roll her out at party’s to perform. Missie on the other hand finds academia more difficult, and so everything takes a little longer for her. She wants desperately to have a ‘thing’ and is trying to find it, she’s tried guitar, Guides, dancing and is currently on drums, but things don’t come as easy to her so she tends to lose interest quite quickly. We don’t let her off the hook until we’ve completely exhausted the hobby.

Where she does excel is sport (no writing required), and is captain of her netball and hockey, but this is only done at school and it's not something she can really do at home as they are team sports. It’s really difficult having to balance the needs and emotions of two daughters at equally difficult ages without it tipping favourably in one daughters direction every so often.

There is a sibling rivalry developing which I never had with my brothers, I think thats because they were so much older than me, they were boys so no direct competition, and they’d moved out by the time I was a teenager, so I can’t quite work out what the best thing to do is in this situation.

We compliment Missie when she is doing well, we encourage her to try new activities so she can find her ‘thing’, and we stress that the most important thing in our house is to be the best that you can be, not the best. I’m starting to be very aware of how much we compliment Tallulah, how much attention she is getting and how that is affecting Missie, but it seems unfair on Tallulah to restrict her positive attention as she puts her hand to more things more often.

I also know from experience that the hormones aren’t helping Missie’s mood. When moods begin to swing it feels like teens try to rationalise it and therefore latch on to first thing that comes to mind to justify the sweeping sadness, or the anger.

Help!

Should we make our praise ‘fair’?

Or credit where credit is due, even if it is disproportionate in one daughters favour?