Only in the second age but...
Im new. Started yesterday actually. The most obvious and annoying thing so far is the inability to spin the screen, making placements of defenses hard to see and therefore do.
The entire core of the games is about building a fortress and robbing other folks blind by attacking and looting them. Thats the fastest way to build resources.
As other players have indicated, youre always subject to being attacked and looted, so its important to not keep much on hand (upgrade or get plundered).
All the strategy app games are meant to be played periodically over time. If you get plundered, go and plunder someone else!
I use the strategy of being fully upgraded BEFORE moving on to the next age. Its working so far.
Droomr about
Age of Empires: Castle Siege