What are some passages from "The Lady in the Looking" Glass and Mrs. Dalloway that represent the stream-of-consciousness technique?

Let us begin by understanding what's meant by 'stream of consciousness' in this context; it's a literary term with various definitions, but we can appeal to Woolf's own description of it in "Modern Fiction":

Examine for a moment an ordinary mind on an ordinary day. The mind receives a myriad impressions—trivial, fantastic, evanescent, or engraved with the sharpness of steel. . . . Let us record the atoms as they fall upon the mind in the order in which they fall, let us trace the pattern, however disconnected and incoherent in appearance, which each sight or incident scores upon the consciousness.

'Stream of consciousness' writing is a hallmark of early twentieth century modernist writing and Woolf is an excellent exponent of this style. In "The Lady in the Looking Glass," the eponymous looking glass is utilized metaphorically in order to provide insights into the character of Isabella, the 'lady' in the title.
In this passage, Woolf describes the 'myriad impressions' received by her mind when she considers Isabella Tyson's drawing room:

The house was empty, and one felt, since one was the only person in the drawing-room, like one of those naturalists who, covered with grass and leaves, lie watching the shyest animals—badgers, otters, kingfishers—moving about freely, themselves unseen. The room that afternoon was full of such shy creatures, lights and shadows, curtains blowing, petals falling—things that never happen, so it seems, if someone is looking. The quiet old country room with its rugs and stone chimney pieces, its sunken book-cases and red and gold lacquer cabinets, was full of such nocturnal creatures. They came pirouetting across the floor, stepping delicately with high-lifted feet and spread tails and pecking allusive beaks as if they had been cranes or flocks of elegant flamingoes whose pink was faded, or peacocks whose trains were veined with silver. And there were obscure flushes and darkenings too, as if a cuttlefish had suddenly suffused the air with purple; and the room had its passions and rages and envies and sorrows coming over it and touting it, like a human being. Nothing stayed the same for two seconds together.

In this passage, Woolf uses the stream of consciousness technique to offer us a glimpse into Isabella's mind:

Without making any thought precise—for she was one of those reticent people whose minds hold their thoughts enmeshed in clouds of silence—she was filled with thoughts. Her mind was like her room, in which lights advanced and retreated, came pirouetting and stepping delicately, spread their tails, pecked their way; and then her whole being was suffused, like the room again, with a cloud of some profound knowledge, some unspoken regret, and then she was full of locked drawers, stuffed with letters, like her cabinets. To talk of 'prizing her open' as if she were an oyster, to use any but the finest and subtlest and most pliable tools upon her was impious and absurd. One must imagine—here was she in the looking-glass. It made one start.

Mrs. Dalloway, one of Woolf's finest novels, also uses this technique throughout, although less than "The Lady and the Looking Glass," which is written almost entirely in the stream of consciousness style. She uses the technique in order to enter into the minds of the various complex characters in Mrs. Dalloway and this allows us to understand them from the inside rather than from the outside. Unlike "The Lady and the Looking Glass," the consciousness in question belongs to the characters rather than the narrator.
This beautiful passage describes the thoughts of Septimus, while he's sitting in Regent's Park:

Beauty, the world seemed to say. And as if to prove it (scientifically) wherever he looked at the houses, at the railings, at the antelopes stretching over the palings, beauty sprang instantly. To watch a leaf quivering in the rush of air was an exquisite joy. Up in the sky swallows swooping, swerving, flinging themselves in and out, round and round, yet always with perfect control as if elastics held them; and the flies rising and falling; and the sun spotting now this leaf, now that, in mockery, dazzling it with soft gold in pure good temper; and now again some chime (it might be a motor horn) tinkling divinely on the grass stalks—all of this, calm and reasonable as it was, made out of ordinary things as it was, was the truth now; beauty, that was the truth now. Beauty was everywhere.

Here, we get a glimpse into the mind of Clarissa Dalloway, the protagonist of the novel:

One feels even in the midst of the traffic, or waking at night, Clarissa was positive, a particular hush, or solemnity; an indescribable pause; a suspense before Big Ben strikes. There! Out it boomed. First a warning, musical; then the hour, irrevocable. The leaden circles dissolved in the air. Such fools we are, she thought, crossing Victoria Street. For Heaven only knows why one loves it so, how one sees it so, making it up, building it round one, tumbling it, creating it every moment afresh; but the veriest frumps, the most dejected of miseries sitting on doorsteps (drink their downfall) do the same; can't be dealt with, she felt positive, by Acts of Parliament for that very reason: they love life. In people's eyes, in the swing, tramp, and trudge; in the bellow and the uproar; the carriages, motor cars, omnibuses, vans, sandwich men shuffling and swinging; brass bands; barrel organs; in the triumph and the jingle and the strange high singing of some aeroplane overhead was what she loved; life; London; this moment in June.