1 - Are you using the glue stick to coat the glass? You will need to do that. it helps the first layer stick to the glass when printing. It also helps the print come off the glass when done! (Every time I have chipped out the glass it was because the glue was thin / missing and the ABS stuck a little too well.)
2 - Make sure you have leveled the print bed. It can be tedious but it will make a BIG difference.
Tip: check to see if the metal bushings on the print bed are glued in place or "float free" on your printer. If they can move, sliding a thin piece of plastic in the gap between the bushing and print bed so they don't wiggle with stiffen up your print bed. I have found this makes calibrating it much easier. (there should be a thread somewhere going into detail on this)
3 - Make sure you have the lid and door closed. Drafts will make your print lift up on the edges.