Help with mental ray v ray or default scaneline

Can you show results that you're getting and few examples of what quality you'd want to achieve? It's hard to advise something meaningfull without knowing that additional info.

P.S. resolution has nothing to do with image quality.

are you using ambient occlusion on your renders . There are number factors that can create a more realistc render set up ambient occlusion add lights to the scene to add atmosphere. It depend what render engine your using . scaneline vray is more realistic render .

no resolution will not change a bad render or maybe unrealistic render . check lights are set for soft shadows . ths can changed in the settings ambient occlusion is importance of shadows that not cast shadows. example of something that has ambient occlusion is wall the cracks and crevices.without ambient occlusion set up your render wont show and realism will be lost