Look down at it from above when it's on the big ring and it should be exactly parallel to the big ring. If it isn't then put it into the small ring again and adjust the position at the frame clamp.

Can you increase the tension by turning the cable barrel adjuster counter-clockwise a few clicks? If not you might need to put it into the small ring and then take up some cable slack. Mark the cable at the adjustment bolt with a sharpie pen and pull out the cable another half millimeter. On the small ring the cable should be taut but not under tension.