You use an analogy when you say that something is like something else (in some respects but not in others).
For example: a jumbo jet is like an albatross in that they both fly, they both have wings, they can both travel for a long way without landing, and both can sense where they are going; but they are unlike in that they have different means of propulsion, are made of different materials, etc.
Often analogies are used very informally: 'This problem makes me think of X (analogy) - that suggests to me that maybe we could try Y (idea drawn from analogy X)
Analogies can be:
Close / direct: A straight functional parallel e.g. selling science is like selling baked beans or the human arm is like an anglepoise lamp.
Fantasy: What is the image that comes into your mind if you were to solve it in your wildest fantasy or within some other cartoon / fantasy world.
Remote and/or surprising: 'Selling widgets' is like 'Steering an elephant'. These analogies are more likely to challenge assumptions and lead to new insights and ideas - but the parallels they suggest are unlikely to have much 'rational' status. In the extreme, they merge into the use of Random stimuli.
Personal / component: Here you become a component in the system. eg. if you are looking at how to get shells to more accurately hit the target, think of yourself as the tip of the shell.
Placed 10 words on the blackboard and asked the class to pick any two words and try to use ‘Analogies’
E.g. Smile and Sun = Every time you smile, you just brighten up my day like the sun.