What strategies and tactics are currently the most effective for winning in League of Legends?

League of Legends is a game where much depends on successful team fights. Considering this, the champion composition should be balanced. It is necessary to have strong AD (bottom lane) and strong AP champions (jungle, mid). Having a high-mobility champion with high burst damage is also highly desirable, as quickly killing a support or another low-health enemy champion can turn the game around. Champions should also have synergy in their abilities.