• Stay as Lo poly as possible.
• Use quads, Poser likes quads.
• Do not SubD in your modeling app.

Poser has its own way to smooth things out.
In General preferences you can set a default crease angle for imported object files.

And Poser has a build in Smoothing function at render time. => It is a checkbox in your Render settings.
In each and every group of your model you can set the crease angle for that particular group in its parameters palette.
Some groups you want smoothed, others less, and some perhaps not.

It is all in detail in the manual.

Use SubD in you modeling app, only if absolutely REQUIRED.
And , it has been written here, when you DO SubD, clean out your mesh afterwards.

And as a last remark : Smoothing and / or SubD, are 2 different things.
Poser uses a smoothing at render time.
SuBD in you modeling app, adds polygons.

And YES, you can Smooth a SubD mesh.
Its like drinking beer and wine at the same time.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!