Well this is how my Ranked Team wins most matches. We tweak the builds a bit if the opponent team is different and so you can too. Just wanted to show the community this good build.

In team fights we usually go in this sequence. Malphite initates ( if malphite does not have ultimate o misses it retreat ) with ultimate and uses spells and Randuin's Omen. Then Garen instantly comes in and E with Randuin's Omen. Hecraim ultimates in and uses his spells. Cho'Gath Q and E. Cho'Gath ultimate deals tons of damage most likely killing an enemy champion ( GO FOR ADC OR APC ). Ezreal stays at the back shooting and dealing damage. BUT REMEMBER ! THIS ALL HAPPENS IN ABOUT 3 SECONDS. SO BE FAST. IF YOU DONT MALPHITE WILL DIE FOR NOTHING. :3