Until I got Kiba (Ninja War) and Kabuto, Sakura/Zabuza/Kakashi worked really well for me. Put Sakura in the back and Zabuza right in front of her, and fire main in the back with Kakashi in front of him. Only problems are Sakura isn't the best healer (thus Kabuto), Kakashi's clones are weak (I just got a better ninja but haven't awakened him yet), and Zabuza's Mist is worthless (hurts more than it helps). But the teamwork is great and got me through to level 44 in 13 logins, so...