I think it's interesting here to see how the Lord fights his battles with his nation. It's good parallels to how he also does so with our own difficulties in life.
One theme I like a lot is how it is often said that the Lord has already given you this land. The promises of the Lord are sure, he talks about them as if they were already fulfilled. To the armies of the Israelites, they are simply going in to claim the blessings, once they continue in their faithfulness.
A history of what nations were attacked, how, in what order.
See Deuteronomy 20 for the rules of going to war.
Then, once the army marches to battle,
In the case of the Canaanites, exceptions are given where all is to be destroyed: Hittites, Amorites, Canaanites, Perizites, Hivites, Jesubites. The reason given is because of idolatry and their abominations, which has been the cause of the downfall of Israel itself for years.
Here's what happened as Moses prepared the company of Israel to enter Canaan, seeing how they match up with the commandments.
First, Moses sends spies into the land of Canaan, one from each tribe, to report on its condition (Numbers 13:1-3, 17-20).
Later, some Israelites try to go to battle on their own. They are warned not to, and those who try to attack the Canaanites are slain (Numbers 14:42-43).