Basic CS:S Map Tips
Every serious mapper wants to make a map that (a) has great gameplay, (b) great framerates, and (c) looks good. I would like to share with you my thoughts on cs_italy, and why I think it is one of the very best maps out there. I hope that mappers can find some of this useful, and keep it in mind as they build their next map.
The right size: not too big, and not too small. CT's can't camp, because the T's can quickly get behind them. If CT's grab the hostages, T's can easily get to the hostage rescue point to make one final stand. Maps that are wide open like de_aztec and de_cbble are too sniper-heavy. Italy allows you to survive with a variety of weapons, including the sniper rifle. But it's not a tiny map, like cs_twilight, which gets boring after you've played it a couple of times.
Z-axis: thanks to sloped roads, stairs, overhead walkways, windows, and of course, crates, there's plenty of verticality in this map. As you turn a corner, there are potential threats from above and below (see various screenshots below). The red dots show various ambush spots. While de_dust is a good intro for new players, I think Italy is more enjoyable for experienced players. You can't just rush Rambo style everywhere; you need to work as a team to get through the choke points.
Less is more: maps like cs_office and Valve's de_inferno are really heavy on eye-candy in the form of static props, and as a result tend to be more laggy in online play. Italy may not be as pretty as de_tides or de_inferno, but it plays smoother online. It uses some sounds to convey the old-town theme, and a couple of decals. Breakable furniture is minimal, and it's in otherwise bare rooms so your frame rates don't tank.
The Apartment: T's can get to the Market and Cellar before the CT's, so the Apartment becomes a tempting option. But you never know how many T's will be behind door #1. Or maybe they're behind door #2. Or maybe they're waiting outside, on the roof. Or maybe they're waiting at the end of the road, with sniper rifles. Even if you survive this far, you know there will be snipers waiting for you as you approach the hostage house. It's the uncertainty that makes the Apartment great.
Lighting: brightness is pretty consistent throughout the map, so you can see your opps (if you know where to look). cs_havana and de_aztec have some spots that are pure black, and I hate it when I get killed by an invisible opponent.