Ever since I started experimenting with my UP! 3D Printer, I have had issues with part warping. The warping is especially bad when the parts are made with solid fill and take up a lot of room on the build platform. I was getting pretty good results using Kapton tape alone, but when a new and difficult part came around it wasn't cutting it anymore.
I found TechShopJim's great instructable here: https://www.instructables.com/id/100-Warp-Free-Make...
about how to make an ABS slurry to help parts stick to the platform. This worked pretty well for me, but I had trouble with applying a thin layer and with storage of the slurry. This instructable details a similar technique that gives me a little better results with less effort, and an additional step to really help warp proof your printer.
Here is what you need to get started:
-Kapton tape (this method might also work with masking tape, but I haven't tried)
-Small squeeze bottle (http://www.mcmaster.com/#1902t14/=pmfznz)
-Scrap ABS part
-Optional: cardboard and tape for draft shield