I know you said you want to do a generalized way to make iced tea but you should really show how to cold brew tea. I prefer cold brew because it gives it a lighter taste with no tannins and its really quite easy to do.
Simply fill your pitcher with cold water and add the proper amount of tea leaves (~1 tsp per cup). I normally leave all my teas in the fridge for about 4 hours, if its rolled then try 6 hours. Then just strain and enjoy. I've read that your not supposed to cold brew herbals and flowers because of toxins, but I can't verify if that information is true.
Here is where I originally found the article: Cold Brewing