Cut up the lettuce, place in a big bowl, and toss in the feta cheese. If you think you'll have leftovers, then keep all the other salad ingredients separate, it'll store fresher this way. If you are feeding a bunch of people, go ahead and toss everything together.Prepare the dressing.In a large bowl put an individual serving of lettuce/feta mix, add some corn, tomatoes, bacon, and onion slices. You could also add in some chopped avocado now, or you could just top the salad with avocado. Add two or three tablespoons of the dressing and toss with tongs. Transfer to a serving plate.