I usually stick to these rules, but of course they can vary depending on the specifics of a project:

1. Wall thickness of the lattice strands: My rule is to not choose a wall thickness below 1 mm. This ensures a good balance between stability and printability. Too thin can be problematic, especially in terms of structure and handling after printing.

2. Proportionality of the lattice structure: I make sure that the size of the lattice cells fits the overall part. Larger parts require larger cell sizes. This not only helps with stability, but also with keeping the part inside free of powder. Smaller cells are not always better, as they can make removing the unmelted powder more difficult.

3. Selection of the lattice structure: I find that not all lattice structures are equally good when it comes to saving weight while simultaneously increasing strength. Some structures simply have too high a volume. So, I always make the decision for a specific lattice structure with a view to the specific requirements of the project, considering material use and the desired mechanical properties.

These guidelines have emerged from my experience and have proven useful, but of course there is always room for adjustments and experiments, depending on the unique requirements and goals of each project.