Even in her very first novel, Harry Potter and the Sorcerer's Stone, J. K. Rowling reveals herself to be a master of literary techniques. We will examine three of these (out of many more): irony, symbolism, and the use of foils.

Harry Potter is the most famous wizard in the world. At only a year old, he defeated Voldemort, the most powerful dark wizard in centuries. Yet as the story opens, Harry ironically doesn't even know he is a wizard. For the past ten years, he has been living with his aunt and uncle, who are the most mugglish of Muggles. Petunia and Vernon despise anything to do with wizardry, and they are determined to knock anything unusual right out of Harry by keeping him as downtrodden as possible. Of course, it doesn't work. Harry is a wizard, and he always will be. That's why he turns his teacher's wig blue, finds himself on top of the school building, and frees the boa constrictor. Harry doesn't understand why such odd things happen to him until he finally receives his Hogwarts letter.

Irony also plays a role at the end of the novel. When Harry goes through the trap door, he expects to find Snape, yet ironically, he discovers the person he least expects: the stuttering, fearful Quirrell. He also learns that Quirrell is the one who has been trying to kill him all year and that Quirrell is the servant of Voldemort. Snape, on the other hand, has been working to save and protect Harry even though Snape tends to be downright nasty. Indeed, things are not always as they seem.

Further, Rowling fills her first Harry Potter novel with symbolism. Harry's cupboard under the stairs, for instance, symbolizes the years of abuse he has suffered at the hands of his aunt and uncle. Diagon Alley symbolizes all the strange delight of the wizarding world as Harry is first introduced to it on his eleventh birthday. The purchase of his school supplies, especially his wand, symbolizes his entry into that world. The Hogwarts Express symbolizes Harry's full entrance into the wizarding world, physically as well as mentally and emotionally. Hogwarts itself becomes Harry's home, both symbolically and actually, as he discovers who he really is and where he belongs.

Rowling also uses foils, pairs of characters that are largely opposites, to highlight the characteristics of each. Harry and Draco Malfoy, for instance, are foils with their opposite backgrounds and outlooks on the way the world should be. Harry and Voldemort also serve as foils, and even symbols, of good and evil, true survival and a mere half-life. Snape and Hagrid are foils in a sense as well. They both have black eyes, but Hagrid's glitter in affection and love while Snape's are cold and empty. They both work to protect Harry, but they behave in very different ways toward him otherwise. Dumbledore and Voldemort are foils, too, for they use their powers for great good and great evil, respectively.

Three literary techniques that Rowling uses very successfully to pull us into her imaginative world are humor, contrast, and imagery.

The novel's opening, which highlights the exaggerated stupidity, meanness, and conventionality of the Muggle Dursleys, as well as their abuse of Harry Potter, brings us into the story, makes us laugh, and builds sympathy for Harry. We are soon rooting for him to succeed against the hot-tempered Vernon, petty-minded Petunia, and bullying, spoiled brat Dudley. This humor continues, if in a more dead-pan way, as Harry attends Hogwarts. For example:

What happened down in the dungeons between you and Professor Quirrell is a complete secret, so, naturally the whole school knows.

This light-hearted approach to a serious theme keeps the book from becoming preachy and unbearable.

Rowling also contrasts the dull, pedestrian, unimaginative Muggle world with the magic and enchantment of the wizarding world. She contrasts Harry's low status in the Muggle world, where he is treated with contempt by his adoptive family, with his high status in the wizard world. The two worlds are opposites of each other, and with such a stark contrast, who wouldn't want to leave the Muggles behind? The following passage contrasts Harry's two very different positions in the two worlds:

A breeze ruffled the neat hedges of Privet Drive, which lay silent and tidy under the inky sky, the very last place you would expect astonishing things to happen. Harry Potter rolled over inside his blankets without waking up. One small hand closed on the letter beside him and he slept on, not knowing he was special, not knowing he was famous, not knowing he would be woken in a few hours' time by Mrs. Dursley's scream ...

Most of all, in my opinion, Rowling is superb at using imagery—which is description using the five senses of sight, sound, smell, taste, and touch—to paint a convincing and compelling picture of her fantasy world. You really feel that you are there: that this is a real place coexisting with our more mundane world. The following example shows both imagery and Rowling's trademark humor, as Neville tells how he first performed magic:

Great Uncle Algie came round for dinner, and he was hanging me out of an upstairs window by the ankles when my Great Auntie Enid offered him a meringue and he accidentally let go. But I bounced—all the way down the garden and into the road. They were all really pleased, Gran was crying, she was so happy.

If you want to be very detailed in this answer, as you read you should search for examples of figurative language (similes and metaphors).  Rowling uses several in all the Harry Potter books.

On a broader scale, however, the most noteworthy literary elements for analysis in any of the Harry Potter books are going to be things like point-of-view, setting(s), symbolism (in objects, characters, and the many symbols--used as labels--found throughout Hogwarts), and foreshadowing.

Symbolism is probably the largest and easiest element to look at.  This book is the first in what becomes an entire series of fantasy books that encorporate very unique story lines with very traditional elements of good vs. evil, magic, mystery, and fantasy.  Everything in Harry's world is symbolic of something else.  Consider for example, the four houses at Hogwarts, the symbols associated with each, and the traditional associations that come with each.  Consider the difference in symbols used for good vs. evil and the way each character is associated with either an animal, natural element, or some other identifying object that gives insight into his or her personality.

Additionally, you could analyze the above techniques through one of the main themes of the book.  Finally, because the story is written at about a 5th grade level, you could look at the elements of foreshadowing throughout the story as the mystery (and Harry's historical back-story) are slowly revealed.