Hi ya :)

Like they said- Lighting is almost everything. Play with different sets, there are thousands of them available, may free.
But sets are just a starting point- move them around- add lights, change intensity.
Play with them!!! it;s the very best way to learn. Each picture is unique and demans it's own lighting.

Play with Poser- it's really such a big program that studing alone isn't enough. The BEST things happen by accident.
Many will say you have to plan out each aspect of your render before you start. Personally, I never had a pic end up as the image I had in mind, lol. Just see my last one- it was SUPPOSE to be a bird sitting on a branch. See what planing gets ya, lol

Poser is a collectors dream and nightmare- the more you gather the wider the range of ideas you'll have, lol, and the bigger your runtime will get.

And lastly, Poser is  a stage. Use it for more then character rendering.

.......Have fun!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!