First layer Z-height is key. The distance between the print bed and nozzle should measure about 50%-75% of your layer height. A sheet of regular 20# paper should just slide between with a small amount of friction.
Spend time leveling your print bed. It’s important to get it right, and in most cases the settings will stay usable for a long time.
As you adjust layer height of your prints, your starting gap between the nozzle and the print surface may need to change. Prints at 60 micron layer height will need a smaller starting height than prints at 250 microns.
For ABS, a heated bed is required, but even the heated bed isn’t foolproof. It’s common to print onto either Kapton or PET tape, and increase stickiness by applying a mixture of ABS scraps in acetone or a few light coats of aerosol hairspray. Use only on a cold bed surface and away from any moving parts in your printer.
For PLA prints, we favor moving to heated beds, especially glass (clean, no fingerprints!), or any surface covered with blue painter’s tape. For extra-large flat prints, wipe down the blue tape with 70% rubbing alcohol first.
Printing nylon? Use a Garolite (fiberglass-epoxy laminate) bed. It’s not a solution most people can pick up at the local big-box store, but it’s widely available online. This material is sometimes referred to as “G10.”
Try BuildTak (buildtak.com). It’s a slightly textured plastic surface specifically created to increase print adhesion. These sheets are available die-cut for a number of different common printer bed sizes, work with both PLA and ABS, and provide peace of mind for overnight prints.