Income is addressed by building income producing buildings, not military buildings. My priority tends to be lodge, manor, market, hearth at level one, then whichever income producer is cheapest next as levels go up. Then other buildings that are terrain dependent (isle, glade, etc) if available and desired. Last and least important when the economy is humming, urban/thorpe/homestead based on the stationed men at arms.

Duchy buildings are useful but not high priority the way they are for vampires. Though for my playstyle I do replace any Nightmare trods at the first available opportunity.

I also tend to start as a vassal (or swear fealty to a neighboring court if I start as a custom character) and make my liege primarily responsible for defense while I focus on snowballing both economy and territory. I think most players don't do this, but it has been my preference since I started playing CK2.

Naming is OP AF.
Their teleport is insanely good.
They have a slow start because you have to max out the range, the legit targets, the duration etc of your gifts in seperate skill trees. With maxed out range, duration etc. fae get very strong.

For money:
Early game: raid by changing agenda to militant, if you're not, with no cost beside different faith opinion minus.
Stewardship perk: Golden Obligation
Capture and hold Paris
Hold forest or taiga counties, especially one with mine, glade building line cost no gold but reduce build cost + build time by 15% at max level
+ stewardship special building
etc.

Magic:
Need time to max out realm perk. Here are some stuff you can do with required perk:
- Give foe massive minus to territory through weather cantrip that last "forever"
- Kill elder vampire instantly by imprisoning and execute as long as you have enough prowess
- Steal any and all artifact instantly without journey
etc.