I am currently playing my first barbarian campaign as the Britons. Having now conquered about 6 areas now I am finding cash a little tough to come by. The setting are VH/VH and I have made efforts to build up my economy.

So far I have been systematically enslaving as I go, in my last campaign (first as well) I systematically exterminated but I figured with the brits such a 'bltzkrieg' tactic would run out of steam, so a more long term stategy of building up my economy/population was needed.

What is the best thing to do?