And there is another problem. You will always find stretching happens again after you finish. That is because you changed the models topology and the predefined UVs stay the same. Thus you have to arrange them to fix.

Method 2 seemed unefficient at the very beginning and actually it wasn't efficient at all. The reason was that you had to undo a lot when reducing the model's resolution. But what was the benefit? In my original opinion, method 2's advantage is that the low-poly model would have exactly the same UV layout as the high one. Because I had to map the high-poly model first and then decrese the resolution, I thought the UVs would stay static since they were already defined. But I was wrong. If you don't know why, don't worry and I will tell you later.

Someone may point out that I would also delete the wrong edges and mess up the UVs. It is true, but I do think people are more cautious when they are only doing deleting. So more likely, they will notice the wrong steps before it causes great waste of time. Again, you can display the UV boards in Maya so that you won't make such a mistake.

Another reason I chose method 2 was because I thought the low-poly mesh would have more similarities to the high-poly model if it was a simplified version of the high one.

I modeled my high-poly model using the popular box modelling method. Since this article is not about modelling, I won't explain how to model the orc. But I do have a tip for beginners.

 I think the bigest difference between experienced modeler and begginers is how many points you can handle at the same time. Rookies always see experts manipulating tons of points on a model and making great details. However, when they try, they find it very frustrating to pull or push points and they always end messing up the geometry. So when you are learning modelling, keep everything simple first. Don't worry about details, you'll master those techniques as you gain more experience.

Figure 3 and figure 4 show the model I modeled.

 
Figure 3    Figure 4

I planed to add more details to the model and applicable details were veins and scars.