2 things to check here:
1) Check the spacing/ clearance of the hotend to the bed. It should be the height of a thin piece of paper.
2) Did you clean the bed/glass? A good wash with soap and/or window cleaner should do the trick. Do NOT touch with hand. Oil is not your friend here.
SOME ADDITONAL HELP:
1) Hair spray does wonders for PLA
2) ABS juice/ glue stick(purple) does wonders for ABS
3) Some say printing on Kypton tape/ Blue painters tape works (never tried these since the above 2 works for me)
Good luck!!