In addition to the ideas and information provided above, Napoleon created power for himself by initially creating an alliance with Snowball and Squealer to set up the terms of Animalism based on Old Major's speech. The pigs realize that the other animals on the farm have been moved by Old Major's ideas, so they put these into practice. The animals have respect and trust for the pigs because the ideas of all the animals have been heard. From this base, Napoleon begins to take advantage of the animals' respect and trust as he starts to instill fear among the animals. His dogs provide fear as do his tendencies to do away with anyone who gets in his way. The killing of Boxer sets the farm on edge, but all are afraid that they might be next if they protest. So, Napoleon uses fear to maintain his power.
Hey, I have a big exam on this book tomorrow haha :)
In many ways, Napoleon was only able to get and maintain power through violence. During the debate over the windmill, Snowball had won over the rest of the animals until Napoleon ordered the nine dogs (who were the nine puppies he took away at birth) to attack him and expel him from the farm. If it wasn't for this, Snowball would most likely have won.
After he managed to get power, these dogs continued to be his method of maintaining power - they were like his personal thugs. An example is the four younger pigs who often challenged Napoleon but, each time they did, the dogs growled at them to scare them into silence.
During the Battle of the Windmill, we are able to clearly see Napoleon's weakness - he is actually a bad leader. In comparison to Snowball's leadership at the Battle of the Cowshed, many more animals died due to his lack of leadership skills. During this battle, the animals are extremely close to losing and, had it not been for Napoleon's dogs, they would have lost. It is down to these thugs using violence, that they won. Again, in comparison to Snowball, Snowball won through his ability to lead the animals whereas Napoleon gets his 'big boys' to use violence against the farmers.
i hope this helped :)