Could you help me to organize my first trip in London for 6 days!

We are not your free travel agents here.

Take a look at some guidebooks, check out the "Destination" info here on Fodors, then come back with specific questions.
http://www.fodors.com/world/europe/england/london/

It would help a lot if you could tell us a bit more about yourself.
What sort of age are you?
What interests you: art, theatre, history, shopping, museums?

You got accomodation?
You understand what the tube is?
You know how you are getting from the airport to the hotel?
You understand about the driving on the left, the no guns/mace/knives rules?
You understand about the weather?
You know that pubs do not have waitress service?

so all set
What do you want to do?

"<i>Could you help me to organize my first trip in London for 6 days!</i>"

Sure we <i>could</i>. But you've given us ABSOLUTELY NOTHING to work w/ here. Sort of like asking "I'm going to the USA - what should I do?"

When?
What sorts of info do you want? - attractions? Accommodations? Transport? Weather/wardrobe? Shopping?
Tell us something about you . . . . . Anything???????