First you have to go to CHEAT, set your money 500,000, and press ADD 10 TOKENS. Also press UNLOCK ALL BUILDINGS. Build a City Hall. After doing this, build a road. Put Utility Centers on either sides. Now, click on the XL button and go to the button with the ARROWS. (TRADE Icon)
Put Electricity all the way up. (TRADE WITH OMNICORP ONLY) You will get lots of money. Now, press the button that looks like a GAME CARD. (SAVE Button) Press start over. The trading cashflow will go up 60,000 more than you traded with. ONLY do this when starting new cities.
Related: Cities XL 2012 Trailer