I'm going to add one more thing here that hasn't yet been said: calibrate, calibrate, then calibrate again! Your motion control calibrations stack and average each other out, so preforming a calibration multiple times can help with your accuracy! You also need to recalibrate *every time you start your wii u*, as the setting doesn't save when you turn it off. I always warm up in the training room every time I start up, so I take the time in the to calibrate my controls. On average I find I need 3-4 calibrations before it feels comfortable to me but YMMV. When testing, I'll snap the controller back and forth several times and watch for any jitter or pushback,and check to make sure my targeting reticle stops where I expect it to. When that goes away and I get consistent performance over several snaps, I know it's calibrated good.
As a pc gamer with keyboard/mouse preference but very little experience using console controllers, I actually found sticks to be awful to me. I can't aim with them, they feel like they slow me down and are unnatural. As such, I can't really help with the transition there, but I will say I frequently use the sticks to make wide, sweeping movements, and do any aiming with motion. I'll also combine sticks and motion for 180s,that way i can keep my motion sensitivity 0.5-1 points lower on average without worrying about making it too hard to quickly turn around. Experiment and find what works best for you!