Want to make the villain easier to hate? have good reasons for the acts (s)he performs, but don't make them visible to the reader. When you understand why someone does something, it is harder to hate them for it. You could always go for unreasoned acts of evil, but in the long run, they're not nearly so dangerous as the villains that have clearly defined reasons that the "good guys" simply cannot comprehend, let alone accept.

Here's a quick example:
[b]Good view:[/b] He regularly flies out on his dragon, randomly killing female children and slaughtering their families.
[b]His view:[/b] He knows of a secret prophesy that his reign will be ended by the child born of a green-eyed girl born after a certain year or at a certain time of the year, thus the only solution to prolonging reign is to ensure that there are no such girls to give birth to his bane. 

In that example, he has a good reason, yet it is not apparent to the "good guys" why he does it, and when they can't know why, it is easier to hate.