Today's RepRap lessons

Use "Cool"
otherwise layers that draw quickly just blob around and don't bond.

Use the "Orbit" method of the Cool module
not the "slow down" which just lowers printhead speed until the layer takes the requisite number of seconds.  I printed a part with "slow down" and when it got to very small layers, it was moving so slowly that the steppers started hitting resonant frequencies with the Y platform and there were horrible shudders in the printed part. Also on the last layer that was perhaps a 5mm circle, it just sat there and melted down into the already printed layers and moved around a little.

I'm printing my first part with "orbit" now - it prints the layer at normal speed then retracts the filament and just moves the head around the outside of the part for a minute while the plastic cools, then goes on to draw the next layer. This seems to be printing very nicely indeed.

Tighten down the extruder idler FULLY
Horse that thing down. I didn't, and the filament slipped enough that the shaved off bits clogged up the hobbed bolt enough that it started not feeding filament for parts of the layer. I had to stop and clean out the bolt and restart the piece.

Power failures
I really should start printing from my netbook and put a 12V battery in circuit. The printer running PLA only draws 4 or 5 amps, so a modest 20 amp hour deep cycle gel cell would run it for several hours. I think this is a better idea than a 1000 watt UPS, and would certainly be far cheaper.