This sounds more like a guide on how to be a bandit and scare away merchants.
One of the steps does include raiding enemy caravans yes, but a few raids is going to be more beneficial than having to wait till you can equip a large enough army to destroy the clan your warring with, if you play 'guerilla' then your going to win a war of attrition rather than one thats going to cost you most of your men and set you back a few weeks to regain everything.