I'm new to 3d printing. I inherited a printer from a guy who left our dept. at work. I've tried several different items and a few different materials but I'm having a terrible time getting things to stay stuck to the glass. Please forgive me if I don't use the correct terms for things, like I said I'm new. I've used ABS, HIPS, and PLA and am frustrated with them all. ABS and HIPS will stick to some degree but usually at some point during the print at least one corner will start to curl up. Sometimes the item is still usable, other times not. PLA doesn't seem to stick at all. I'm using the setting the previous guy left behind. Generally a nozzle temp of 240C and a bed temp of 120C. I've tried increasing these temps with no luck. What am I doing wrong?

Edit: Sorry, I forgot, I have a Lulzbot TAZ 5 printer.

PB2