ziGzaG has written a nice mix of CS strategies and tactics which I think are damn nifty and well-written. I'll pretend like the bunny hopping one doesn't exist and quote from his Italy guide:
From a Distance:Check it out and keep your eyes open because he's adding guides 2 or 3 times a week so his site doesn't get stale.
Long range shooting can become you 'best friend' on this map if you can maintain control of your weapon by shooting in bursts. Stay half way around a corner for extra cover and remember to use your radio if you get ambushed.
Up Close Confrontation:
If you prefer close or medium range battles, head for the marketplace or flank the CT spawn from the right. Be sure to use the numerous boxes and obstacles for cover once you get into a fire fight.
The Art of Confusion:
One of the great things about this map is the ability to confuse an enemy. Use crates, the paintings in the market place, barrels or any other obstruction to leave you enemy wondering where you went. Pop out when they aren't expecting it and go for the kill.