I don't recommend juggling more than one project at a time.
My current WIP is Shadow Bound. I'm a little over halfway done with the first draft and hopefully I'll have that done the first week in August.
Then I'll take a few steps back and leave it alone for a couple of weeks so I can come at it fresh. In the meantime, I'll do a lot more planning on my next novel, code named: Phantom. Not a very clever code name, but oh well. This is the project I've been working on in Holly Lisle's How to Think Sideways course, since most of the planning for Shadows is already done. (How Think Sideways has helped me.)
So on the days I'm following along in the course and doing my lessons, I don't get much (if any) writing done for Shadows. The problem is, I'm at a point now where I really need to focus on Shadows because I need I nice tight ending. This is the hardest part of writing a first draft for me--keeping all the details and twists in my head while plotting an ending that's both exciting and satisfying. All while maintaining voice and character and grammar and setting...
I should probably set Phantom aside, but these thoughts keep popping into my head: "Ask John about musicals!" and "Ask Jenny about music schools!" and "Ooh, do a dot and line exercise for the hero!" It's like I have a little girl prancing around in a candy shop, trying to sample everything.
Just stop. Breathe. And Focus!