So you made a few boards. Or not! Either way, this is a running list of tips and tricks for users - things to do and things to avoid. We make no guarantee with any of these, but we have found that they've helped us in some way.

• Plating is typically avoidable by making vias with a diameter of 40 mil (1 mm). A standard 0.1” header pin can then be pushed through and soldered on both the top and bottom.
• Higher polygon isolation will reduce the chance of bridging to a plane during assembly (since we don’t really offer soldermask). However, it will also increase etch time because more of the substrate will be etched. “Isolataion” is usually a setting that you can edit per specific polygon; 10 mil is the default often, but 24 or 32 mil (or more, though the benefits decrease) will reduce the risks further.
• Slots! We can do them! There are probably a couple of methods for doing this, but the way we've had success is to add the slots onto the “BoardOutline” layer in the software. How this happens depends on your EDA (CAD) software, but in essence, you either need to have your slot in a new gerber (which you can assign to “BoardOutline” in the Import step) or you need to put your slots onto the layer in your EDA that spits out your Board Outline gerber file (in Eagle, this layer is called “Dimensions”). Unfortunately, we haven't found a good way to do plated slots because in the above method, the slot is made after the etching is done (and therefore after the plating would be done). An alternative in this case would be to design your slot as overlapping drill hits which are done prior to plating.
• If you're interested in optimizing your ProtoLaser experience, see the LPKF ProtoLaser Optimization document for more information.

The Book of Kane