The first and foremost way to win on Italy is team-play. Whether its forming a squad to attack the enemy base, or using another member of your team to crouch-jump off while you get into l33t areas on the roof, you won't be able to win without assistance.
Italy is a map of good size, and so there are lots of tricks on the map, and most of the advantages have gone the to the Ts, as there are uphill, in a building with windows for snipers, and a big open space or long tunnel when coming up to the base, so CTs are easy targets. The objective of this map is for the CTs to rescue the hostages from the terrorist's base at the other side of the level.
Counter-Terrorist Strategy
Counter-terrorists have no option on this level but to rush. There just isn't anywhere for them to camp. There are multiple routes to the terrorist base, so CTs would be advised to send squads in each direction if possible, and so covering all possible avenues of escape for the Ts. Any snipers on the CT side should stick to the back, and once an area has been cleared, try and get up onto high ground (i.e. on top of a building) and try to provide some cover fire for the rest of them team, but these positions are also extremely vulnerable, so try to stay inconspicuous, and don't fire unless you've got a good shot, or else you'll be giving up your position needlessly.
Ideally, it should be multiple squads going in all directions with sniper support, but if this is a bit too much for your team to muster, just go for a massive clump of players all heading in one direction, and you should be able to over-power any opposition rather easily. As you have probably guessed, the destination of the CTs is the terrorists base for both strategies, so if the team does break down into smaller squads, they should try and converge on the T's base at the same time, and give each other cover-fire. If its just a single team, totally swamp the base so the Ts are completely outgunned.
CTs must rush on this level, and there is no reason for hiding behind a box anywhere.
Cover all routes of escape. This means to go through the market, to the left of the level and through the wine cellar, through the balcony at the start which can be accessed by climbing boxes, and through the multiple alleys. Its important to keep the Ts contained, or else they can come around from behind and bite the rest of your team up the ass.
Once most of the Ts have either been killed or beaten back, close in on the base. You'll be needing a sniper to pull this one off, as you will come under heavy fire if you just try to run up to the base from the tunnel or the courtyard.
For Clan games, try and co-ordinate when the different CT squads converge on the base, as only one of these will become the target of sniper fire, while the others will be more or less free to charge in and start firing. Simple enough.
Or alternatively, if you the Ts are just going to camp, a massive rush in one direction will win you the match.
If the Ts decide to rush, the market is a good place to hide, as the boxes and crates make it difficult to shoot through, and its always easier to shoot outwards than it is in. Shoot the chickens as well, so they don't get in the way later (plus, its fun).
Unlike the CTs, its best if the Ts stick together like glue, as given the CTs superior weapons, you'll be needing the extra fire-power. And most importantly, shoot out the radio at the start of the level. No-one likes listening to it.
