What you'll need:
Acrylic: Polycarbonate ("Lexan") won't cut on the laser. 1/8" thick (often 3mm, around 0.118") works well. Thicker will be more difficult to bend. Fluorescent or smoke colors can add a nice touch--I got this fluorescent blue from Inventables.com: https://www.inventables.com/technologies/fluorescent-blue-acrylic-sheet
Precise measurements of locations and diameters of knobs, jacks, ventilation holes, circuit board mounting holes, etc.
Form for bending (more later)
(If you live near Ann Arbor, MI, you'll find these tools and more at Maker Works, a makerspace. Many makerspaces will have a strip heater if they have a laser cutter.)
Step 1: Create your laser file
Plan on a reasonable radius on bends. I used 3/8" here for appearance.
Consider using slots instead of holes for mounting things to ease assembly.
Give yourself clearance around components that stick through the acrylic, especially threaded shafts (e.g., volume controls, jacks).
If you'll be using a form, you may wish to add an indexing hole or holes if you don't already have one naturally. In the graphic above, this is the small hole in the center.
Remember to factor in the radius of the bends when planning the overall length of the flat stock. I used a 3/8" bend radius, so the material is shorter than if you had a perfect 90-degree bend.
Measure your actual material thickness.
If you are using a graphics program, remember that for the Epilog laser drivers, cut lines must be thin ("hairline").
Add labels, part numbers, logos, or other engraved content. If a piece is slightly non-symmetric (this one is--the PCB mounting holes are not the same distance from each edge), you might want to put a subtle indication on it. I placed some labels and logos on the top of my enclosure, but didn't on the bottom.