Similarities and Differences:

Similarities and Differences tries to free your thoughts from their usual tracks by deliberately introducing the unusual and strange. Therefore if you think that the technique sounds weird and you feel strange doing it - its working.

The process

Start by deciding on your problem as an object, rather than an action. Then decide on another object. This can be anything, but things of an organic nature often work best. Write down all the similarities you can think of between your problem object and the comparison object. This can be as simple as they are both white, and can include actions they perform or abstract characteristics they have.
Once you have run out of similarities, start on a list of differences. These should refer to actual characteristics of one object or the other and is likely to result in a much longer list.
Once you have a completed list you can group similar elements together. It is then a case of first looking at the similarities and determining if the functionality completely overlaps, or if the missing elements might add to your original problem object.
You can then move on to the differences and determining whether the way that a function or characteristic is exhibited by the two objects can be used to provide new ideas for your problem object.

An Example

Perhaps your problem object is an IR (Infra Red) sensor, and your comparison object is the human eye. These have obvious similarities (optical system, image forming, delicate, etc.) which suggest that the two are closely related. From the similarities the question comes as to the moving of the human eye vs the fixed nature of some IR sensor.
From the differences other questions arise. The human eye has variable resolution across its field of vision, the IR sensor may not. The human eye constantly maintains small movements which can be used to enhance apparent resolution (literally taking another look), but vibration may be seen as a fault in an IR sensor. The human eye usually comes in pairs, but the IR sensor is usually singular?

Conclusion

Taking these finding together gives the innovator the opportunity to think outside their usual understanding and potentially find new ideas for further investigation