I had trouble with PETG at first as well, but finally got it dialed in. Now it sticks great, and usually self removes when completely cooled. Of course every printer and environment is different, but for me this is what works in Cura with Atomic PETG:
First Layer Width: 110%
First Layer Flow: 120%
First Layer Speed: 20mm/s
Fan: 25% (Off on first layer)
Use skirt to babystep your z-offset until you have the perfect "squish". From there the only thing you'll have to worry about is stringing, but that's always a challenge with PETG. I really like Atomic's CF PETG as it strings less and produces strings parts.