Print a little hotter… increase the extrusion temp by a 2-3C. And make sure to keep the cooling to a minimum.
The higher extrusion temp will help bonding of the ABS with the previous layer. The lack or less cooling further encourages the bonding.
If you’ve adjusted flow rate or multiplier for dimensional accuracy, try increasing by a 1-2%. Thicker extrusion will again help with bonding.
An enclosure will help as everyone has suggested. A make shift enclosure can be create by draping a blanket over the printer. Make sure the tent doesn’t interfere with printer movement or the print. Increasing the ambient temps will allow the ABS to cool slower and reduce the contraction/shrinking effect.
Unfortunately, its a trial and error approach since everyone’s printing environment is unique.