>>4656
If you underfund your military, either army or navy, it will have direct and very visible effects on their performance. If you look under the military in the country menu, then you'll be able to find your forcelimit. If you have more troops than that forcelimit, you'll start paying absurd sums extra for those troops.
So don't go over the forcelimit.
Also, you might want to focus on either the English Channel trade node, or the Genoese trade node. Both are end nodes, so they can sponge up a lot of money. Money that can finance your fleets and armies.
You might also want to plan your forts better, since overlapping forts can create huge extra costs in your budget. Remove forts that are just overlapping, and create forts at the borders you'll most likely be attacked on.
Since you're allied with Austria, I'd recommend that you make your moves to destroy Aragon and seize the river estuary and important center of trade down in Valencia. That'll make you able to seize most of the Genoese trade, since you're allied with the emperor and can't just eat all of the Lowlands.
Also, check the economy tab in the country menu and find out what you're throwing your money away on. It should be pretty apparent to you where your expenditures are, when you've already slashed army and navy, yet still manage to make a deficit.