Foreshadowing is the art of adding hints or allusions to what will happen in the story next. If used right, it will engage the readers and make your story stand out. A lot of great writers in the history of literature have used this trope in their writing, moreover, any genre of creative writing can contain foreshadowing. Here are the basic principles to keep in mind when we talk about foreshadowing.
It might be a hidden letter in the mailbox, a strange look from the butler or a careless phrase of the main character. Adding a clever detail will make your reader sit on the edge of their seat. What was the content of that letter? Why did the butler have so much suspicion in his eyes? Why did the main hero utter such a phrase in this situation? These questions will stay throughout the story at the back of the head of your readers, only to be resolved in the most creative way possible at the end of it.
Keep Them Separated
It is better to add your foreshadowing tropes all throughout the story, and not concentrated in one place. Think about your details as if they are ingredients of your soup: adding salt, pepper, mint, ginger and garlic all at once will hardly bring you fame as a culinary chef. If you need to, reread your writing again, and try to put an allusion to what might happen in the beginning of the story, in the middle and towards the end. This way, the reader will anticipate and expect the events, keeping himself interested in your writing, and then realize everything during the grand finale.
Subtlety is the Key
If you state that near the scene of the murder some big gardening scissors were found, it will not take a Sherlock Holmes to realize that the killer is probably the gardener. Try to concentrate on the subtlety of your details, and present them with as much nonchalance as possible. The reader will be intrigued and left wondering. Some writers make the mistake of getting too broad with the details to pay attention to the main part of the story. Consider it as if dressing up for an upper-class party: an elegant wristwatch may do the trick, but adding expensive jewelry, earrings, a brooch and a couple of rings will turn everyone off.
Let Them Put the Pieces Together
Sometimes we do not give enough credit to the readers. They might have a little bit more insight than we think, so it is not necessary to explain the meaning behind every single detail that you have added. Your writing is a platform through which the reader can make their own conclusions. Sadly, not always it will be interpreted the way you want it to be, but multiple interpretations in itself are the beauty of writing. If you are not sure about the use of your foreshadowing, give your story to a couple of friends. Their opinions and feelings will vastly differ, and you will find their review helpful for your next pieces of writing.