Note the guns they have and if any players CS:GO Skins there may cause a problem for you. Particularly useful at the start of the round is to fire at the bottom of their wall, either on the right of left side.
Many players simply duck behind a wall being shot at by the enemy and more often than not avoid getting hurt badly, or even hurt at all. Firing at the bottom of the wall often brings them around the corner.A great training tool and guide for getting better at Iceworld and many other maps is the Counter-Strike Pwnage Guide.
If you're rusty at anything I've mentioned or need to perfect it, it'll be a great investment and greatly increase your Counter Strike skills on any map. Iceworld may not be the most respected or popular map the game has ever had, but this guide and regular play will greatly improve your skills when put to CSGOSK CSGO Skins.