Getting lost is an age old suggestion but a good one. Put away your cell phone or your A-Z and just wander around. I still do this regularly even though Ive lived here for nearly 10 years. London is a big city and it drip feeds you its secrets sometimes. You will come across things you wouldn't usually, in amongst the Starbucks and pret a mange there are some amazing sights. Just 'being' somewhere is a great experience and one no guide book can help you find.
P Franco, wine shop, bar and restaurant. Amazing wine, delicious small plates (guest chefs) in a very lively atmosphere. The wait for a spot to sit down is worth it.
One of the most special pubs in London, not so much for the place itself but rather for the crowd you will meet there; a mixture of locals, art students, passers by and weirdos. A place to feel at home and share a beer with the staff and/or the landlord (Paul).
I love the George and Dragon Public House. Cluttered deco of silly artifacts and memorabilia and slightly scuzzy around the edges. Great drinking characters, DJs and The White Cubicle gallery in the ladies toilets is difficult to beat.