Also place Squadrons of light ships in the nodes you want to steer trade from. in Demo each barque was worth 3 tradepower in the node it was stationed in. Which if done correctly will magnify the effects of Steering and Collection.
I played as Portugal and Venice and just sent those Trade fleets to each node and then looked at what the ledger said. Basically you want "Trade Fleets" in each node that you have a merchant placed. With the biggest in your Capital node.(I'm not a number cruncher but those were my observations)
Remember these squadrons will be easy to defeat piecemeal like the Pirate Patrols in EU3 and the fact that they can't just stay in port and work, must patrol (as far as I can tell)