Most of the same reccomendations that apply for adhesion to a hot bed apply for a cold one. The first ones to come to mind:

• really dial in the nozzle height


• make the first layer taller than the rest (e.g.: 0.2mm if the rest of your print is 0.1mm)


• print the first layer very slowly


• print the first layer at higher temperature


• use a brim or a raft (on my first printer, that had no heated bed, rafts gave the least deformation)


• turn off the part fan for the first layer


• adapt your model to reduce twisting forces (relief cuts, print it in parts, choose orientation wisely, etc...)

If your slicer has this feature, you could also try to print with a shroud.

Fresh 3M blue painter’s tape coated in a watered down solution of Elmer’s white glue works wonders - even when cold - for PLA.

The tape needs to be re-applied and coated for each print for it to really stick, but it beats every other print surface I have tested for PLA other than PEI @ 70 °C. I’m guessing it has something to do with microscopic surface fibers on the tape...

(I like to print PETG as well, and that sticks too well to PEI, so I use blue 3M tape for both.)