Much depends on the laser cutter and the software being used to create the drawing and/or the software being used to run the machine. I've used some machines where line thickness was recognized and others where line thickness was ignored. I've also used some machines where the software could be set up to automatically account for kerf and others where it had to be done manually in the drawing. I think most cutting services provide this sort of information on their web sites and it may vary from one to the next. If the information is not covered specifically then I would suggest an email to the cutter for a direct answer. Some basic suggestions I would offer are these:
- Make sure all your line segments are joined together as much as possible
- Where you have closed shapes make sure they are actually, and accurately, closed. Otherwise some functions, such as offsetting, may not work properly
- Make sure you don't have lines on top of other lines
- Try to avoid using Splines. In fact I would say avoid them at all costs! Maybe it's just me but I've always had issues of some sort when trying to edit Splines.