user Illustrator (recommended by me) or CorelDraw (recommended by some others).
- set up a document that's 48" x 24", RGB mode. here's is a illustrator template file
- if building 3d things set grid-size matching your material's thickness
- use RGB RED for vector cuts (all the way thru the material)
- use RGB BLUE for vector engraves (part way thru the material)
- use BLACK for raster engrave (part way through, laser moves back-forth across)
- if working with images, "live trace", "live paint" are your friends; if working with anything "pathfinder" is your friend. look them up in Illustrator!