The analogies I use in Physics, the ones I can remember right now, are in the explanation of how the particles behave in expansion and contraction. I resemble particles to people.. when the temperature rises, people need more space and so move slightly away from each other, so expansion takes place and when the temperature decreases, contraction takes place and people cuddle up and so move closer together. The flaw of this analogy is that in water, when temperature decreases, ice takes more space than in liquid form.
I also use analogies with specific heat capacity .. resemble low specific heat capacity with someone who has low tolerance and is therefore very impatient so his temperature rises very quickly, and high specific heat capacity with someone who has a high tolerance and so his temperature rises slowly.
I think that such analogies are good for O' Level, for a certain level of knowledge, but will not probably use them with higher levels because I expect more depth in knowledge. In my opinion analogies can only be used to a certain extent.