how do you guys increase your faction's income?

[Quintus.JC]

Building an arena or it's upgrade could start an gladiator rebillion. I don't want my generals to run into Spartatus and his buddies. They get elephants as well. Scary.

[Quirinus]

It's pretty rare, though. Besides, you can always bribe them back, as these gladiator rebellions mostly happen in the late-game.

[Omanes Alexandrapolites]

As said, fine tuning the military is probably the most important aspect of financial management - military upkeep almost always is the largest strain on any factions' coffers. Disbanding units no longer needed and minimising garrison sizes is often critical to optimising financial situations for the better.

On that note, if you have a city suffering from terrible public order, peasants, in R:TW, are better garrison troops than town watch. This is because of a combination of a higher number of men in the unit, henceforth higher happiness bonus, with a lower upkeep cost. In BI this is not the case though - peasants provide less of a bonus than higher class units.

Another key method of improving income is simply avoiding the construction of unnecessary/less economically worthwhile structures. Although some may think that building anything and everything is a wise move, one often has to consider pay back time and, most importantly, whether the construction is actually worthwhile in the first place.

In the settlement details scroll, the one with the pictograms, a settlement's financial gains/losses are shown on the screen. If the player selects to build a new building, the bonuses provided are shown as faded out items on the + pictogram, while negatives which will be take away are shown as fading out icons on the - pictogram.

Holding the mouse over these fading/faded icons shows the value of the addition/subtraction per turn. Comparing that with the cost of the building shows the potential of the scheme each turn versus the initial cost.

If you really are in financial hell destroying buildings to get back their cash can be a must. As the WRE in BI, this is pretty much the only early tactic which can actually get you past the early phases.

[ThePianist]

How is it that peasants are less good as garrison in Barbarian Invasion?

[Omanes Alexandrapolites]

How is it that peasants are less good as garrison in Barbarian Invasion?

It's due to the "peasant" attribute in the text files.

This reduces the effect of units with the attribute have on public order in settlements by a fairly significant amount. As you may expect, peasants have the attribute assigned to them. All other units, as far as I know, don't have the attribute, so don't have the reduction.