You, the Writer, are a twisted mastermind who puts criminals on the streets, plots their crimes and callously dispenses with their victims.  You toy with the detective, drip-feeding clues and laying false trails, frustrating his enquiries, yet causing cliff-hanging danger so he can’t give in and stop.

The detective, of course, is the reader.

But how do you build up the clues so that the reader doesn’t ‘get it’ too early?  Because the ideal is that the reader gets the answer pretty much simultaneously with your detective character; it doesn’t really work if your fictional sleuth is still blundering around for fifty pages when the reader’s worked it all out…  (‘It’ usually – though not always – being the identity of the criminal:  they don’t call them whodunits for nothing).

So naturally you have to disguise your evidence, especially nearer the start of a story, when the puzzle is at its most obscure.  You have to find ways of giving partial clues.  And then control the pace by which more information gets to the reader so he can reassess what came earlier. Some very simple ideas are below:

Information                            Disguise                                Reassessment after

Voicemail message             Caller drunk                           Found and sobered

Needle is the weapon         Found on drug user                Further clues implicate him

Written evidence                 In a foreign language             Finding translator

Action Point Two:  Continue the above list until you have at least 25 ideas.  Try to link as many of them together as possible in order to generate plot ideas, or if you already have a plot in mind, try to fit as many into your own plot as you can.  To help you feel closer to being a criminal mastermind, practise an evil laugh or two.