Cut the avocado in half, remove the pit, and slice it.
Cook the bacon in a pan until crispy.
Wash the lettuce thoroughly and pat dry.
Slice the tomato thinly.
Toast the bread in a toaster or on a pan.
Spread mayonnaise on one slice of the toasted bread.
Layer lettuce, bacon, avocado, tomato, and the other slice of bread in order to complete the sandwich.
Cut in half for easier serving.