Embed your most important clues within the first 10 pages. This early in the story, readers are going to be too busy absorbing the ambiance, learning your characters' names and getting used to your writing style that they're not going to pay as strict attention to innocuous events such as a spilled glass of milk, a taxi going down the street or a character's self-tinting eyeglasses. Sandwich these clues between elements of action or dialogue that are humorous, provocative or startling.
Example: The character with the self-tinting glasses starts to tell a joke but is interrupted by the sound of a scream in the next room. The scream immediately divert the reader's attention.
Use foreshadowing to plant suggestions that will later prove useful in saving the protagonist's life, decoding a secret or resolving a conflict in a seemingly clever and unexpected way. To paraphrase Anton Chekhov, if your character is going to fire a gun in the third act, the existence of that gun needs to have been introduced in the first act or it will come off as a contrivance.
Example: The heroine's younger brother gives her his treasured penknife as a farewell memento just before she boards a magnificent ship bound for America. She puts it in her pocket and we, the audience, promptly forget about it until the third act when the ship hits an iceberg, the rope pulleys of the lifeboat become tangled and the only thing that can save the dangling passengers is a knife.
Use "legitimate" red herrings. What this means is that whatever you decide to introduce as a fake clue to lead readers astray has to be something that could be interpreted in two different ways. For instance, readers will assume that the reason Edgar rushes to get to the dry cleaners first thing in the morning with a bundle of clothes is that they contain incriminating stains. Maybe he also figured out that the dry cleaners would be the best place to hide these items for a while. Edgar, then, must be guilty of something. Imagine the readers' surprise to learn that the true reason for his haste is that he'd promised his wife to drop them off a week ago and knows he'll be in trouble if she comes home from her trip and looks in the closet.
Incorporate symbolism and metaphors that hint of events to come. Weather, for example, is often used to suggest correlations between the dark clouds that are gathering on the horizon and the darker moods of individuals who are being brought together against their will. Draw on historical events, as well, that tease readers into thinking they can predict your story's outcome based on recognizable patterns. Flashbacks can be used in this same manner.
Enlist test readers to read your book in progress. Quiz them on what they think is going to happen next. If they guess accurately, it's a sign that you're not as clever as you thought you were. Go back and make the changes necessary to keep from tipping your hand too soon. Keep the ending plausible and consistent with the personalities of your characters and the actions they have previously taken.