First, enrich the soil as the conifers will have used all the food. Then decide what you like. Eucalyptus gunni grows fast and can be pruned and is evergreen. Beware of anything that grows too fast because they just keep on and on! And choose something that you can trim without ruining the shape. Mix in some deciduous trees like cherries or birches, or Sorbus (Rowan) for the berries. Position the evergreen trees over windows etc and put the others on either side. Twigs give a certain amount of privacy in winter...unles you are a topless winter sunbather!!