A lot of the realism you see on some renders here is down to a combo of using excellent textures on the figures and good lighting techniques and sometimes , though not always, some excellently done postwork in Photoshop or PSP. There are some who have done very good renders with the base G2 figures and textures that poser ships with however most folk buy further content ( figures, textures, clothes, hair etc) in the marketplace here,or at Daz, Rdna etc. Many also buy light sets, pre-made pose sets though I personally find it more fun and challenging to make my own of those and also changing or making my own clothes and character textures in Photoshop ( not very good char. textutes so far I admit but a learning curve and fun ) For female figures Victoria3 and Victoria4 and Aiko3 (base figures all at Daz) seem to me to be the most oft used though there are others that have their champions ... everyone has their own preferences for various reasons. Welcome to Poser and enjoy !

" Try and be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try and live together in peace and harmony with people of all creeds and nations."
-Monty Python