How do I attract People to my Stronghold?

As you repair and build you get 'prestige' and 'security', shown on the upgrade panel. The more prestige your stronghold has, the more likely people are to visit, but don't build for prestige only. Without security, visitors and your stronghold are at risk.

hmmm so a prestige level of 10 isn't enough? :(

No, far from it.

At least 30 but aim for 35+ of both Security AND prestige. Just remember to recruit right mercenaries (Korgrak, Bard, Dozen/Crucible, Glanfathan Mind Hunter etc.) the ones that either give bonus to Both S and P or give huge bonus to one (if You have Korgrak You'll get what i mean).

And in what frequency do i receive taxes? I got taxes once, but thats it so far... :/

stronghold day? ummm ok... What is a stronghold day? :/

To be honest I don't know the exact mechanics, but it seems to revolve around stronghold events and/or adventures. I think it's a separate timescale from the rest of the game.

I know when the adventures (little quests you can assign characters to in order to get bonus items, exp, etc) each "day" is actually one of your party quests completed.

So let's say an adventure says "2 days" - if you complete two quests one after the other, your adventure will finish right then and there!

I THINK taxes are collected and salaries paid based on in game time passing.