Models

1 - Take Two Impressions.  I don't care if it's diagnostic casts or a final impression.  If my patients expect 2, and I screw the first one up, then I don't look bad.  If the first one's good, the second might be great.

2 - Use the vacu-mixer.  You can't possibly vibrate ALL of the bubbles out of the stone, this machine can.  Your models will never look better.

3 - Superglue, and a couple of coat hangers.  Well... You'll probably want a superglue accelerator too.  This product, called "zip kicker" makes the superglue harden real quick.  It is sold through dental supply stores with wires pre-bent in the shape of an N.  After you have mounted your maxillary cast, articulate the mandibular cast [with or without a bite registration] and use the wires and superglue to hold them together as you mount the mandibular cast.

4 - Sandpaper.  Most people know that this is the best way to smooth out the final plaster on mounted models.

5 - Floor wax.  Yup.  I learned this at a lab.  One coat on the entire model [even occlusally], then 2-3 more coats on the rest [buccal, lingual, and the plaster].  Instant presentation quality.

That's my procedure for models.  No, I don't use boxing wax to create a base.  If I need more of a base, then I will add more stone later.