How to make Southern (US) sweet tea: put about a quart of water in a saucepan, plus 4 cups of sugar and the number of Orange Pekoe teabags you would use to make a gallon (for me it's about 8 normal or 4 family-sized). Bring to a boil and immediately remove from heat. Steep 2-3 minutes. Remove bags and stir to make sure sugar is dissolved. Fill a gallon container with ice. Pour the hot tea over ice and add cold water to fill up. Serve over more ice.
Also, be sure to use Lipton (which is orange pekoe but so are some other brands so specificity helps)... Anything else is subpar for sweet tea (iced Southern US style).