Lines must form a closed contour. Otherwise your part may stuck into the material and needs to be cut out manually.
Please try to avoid overlapping lines. The cutting software will recognise them and calculate them as extra cuts thus increasing the overall price.
The scale must be 1:1. You can check if the dimensions are correct after uploading your design.
If you prepared a typo please make outlines from it. This way if the workshop don't have your fonts it won't be a problem.
If you prepared a typo please keep in mind that the insides of the letters will fall out. If you want to keep them together you need to connect them to the part.
If you have multiple parts please arrange them at least 1mm from each other. This applies if working with non metallic materials. If you work with metallic materials the distance should be as large as the material thickness.
There must be nothing else in the cutting file besides the cutting lines. No title block, dimensions, tolerances, centre lines, bending lines or hatching. Any specifications should be in a separate file and uploaded separately.
If you work with splines please convert them to arcs and lines. The software of laser cutters often have problems with splines creating misshappen forms.