There are some basic concepts related to polygonal modeling that are good practices to follow. Below is a list of guidelines and links to keep in mind when working on your models.
– start simple with a low polygon count. you can add complexity as you go, but it is easier for you to make modification and control the position of the UV textures when you have fewer faces and a low polygon count.
– work with quads (4-sided) polygons. this helps to keep your topology uniform and even distribution of verticies.
– create consistent edge loops. the edges of your model should follow the contours of the shape you are trying to create. By creating edges that “flow” it will help with rigging and animating in later stages.
Modeling with Edge Loops
Realistic Face Modeling
Modeling the Human Hand
Creating High Resolution Polygon Models
HardSurface Modeling in Maya 2012
Hard Surface Modeling tips
Hard Surface Modeling Tips and Tricks