[Zephyrial]

I only clicked around the game for a few minutes, but I have two general ideas: (partially borrowed from the Zynga Handbook of Doom, but you did ask for addictive...)

* Don't have players start with zero coins; give us enough to start off and do something fun or cool (i.e. book one flight, get to a new city), and then lead players into the game's job mechanic.

* It's a terribly silly (and transparent) game mechanic, but I love games with Achivements / Medals / Awards. Either make them all available from the start or (a la many iPhone games) only "assign" three achivements at a time, each with a certain "star" value; get enough stars and you "level up", which comes with a hefty coin bonus. This way, once players have figured out the game's mechanics, they'll continue playing for achivements (and you can use achivements to encourage experimentation with other game features).

[peterbe]

The game starts with the tutorial. You answer three really simple questions and they all give out lots of coins. So, very soon you're on your way somewhere with your coins.

I am working on a "Awards" feature. What I think I will do then is to combine that with big rewards. And the awards should be awarded to you just by playing. You'll have to really work hard. For example, getting 100% on the questions under a certain time.

Thanks for the feedback!

[sunir]

Give enough coins to do --almost-- three things so players are immediately encouraged to earn a few more coins to do the next thing.

[peterbe]

Have you tried the tutorial? The purpose of it is to give you a preview of how you earn so that you can do that yourself from there on.