Are you new to Zynga's newest game CityVille? So This is the right place for you. One important part of Any Zynga's game is you need Social help. You need Friends to help you & vice versa. This game is just like others. You need lots of Friend to up in the ladder (Level)!
After you have completed few missions, this pop-up will come up. Click 'INVITE FARM FRIENDS' If you are a Part of FarmVille (Zynga's other game) they will take you to invite your FarmVille Friends. Just do it, the best thing is according to me one way acceptance; either they have to accept your invitation or vice versa.
Currently CityVille is in BETA, and personally i have facing some bugs. but i have full faith on Zynga, that they will resolve the problem soon. Friends help you to build your city, supply parts, Goods, Work on your City! Have Fun & Enjoy, Don't forget to INVITE YOUR FRIEND!!