I initially used spheres of blutack to level the bed on my Sumpod 3d printer. This worked surprisingly well and was good enough to start testing but wasn't very robust.
For something more robust, I followed Stohn's method. The components I used were:
M5 Stainless Steel Countersunk Allen Screws from ebay,
M5 captive pronged tee nuts from ebay,
9.5x15.9mm springs from a set on Amazon, and
washers from a set on Amazon.
For each corner in turn, I used a screw with a large washer (to spread the force) through the platform without the bed in place to drive a captive pronged nuts into the platform and then removed the screw again.
I then put the springs and bed in place and put the screws back in (using smaller washers). I screwed it together leaving a bit of space to tighten it during levelling.
I don't know how others are doing the actually levelling, but I used replicatorg with X axis and Y axis homed then moved the Z axis until it was less than .5mm from the bed. I then attempted to slide a business card under the nozzle; and tightened the closest screw until the card wouldn't go under and then loosened it very slightly until the business card just went under. I then moved slowly towards another corner. Every 10mm (or sooner if it looked too close), I tried the business card and, if necessary, adjusted the screw (of the corner I was heading towards).
I'd welcome comments about better processes for bed levelling.