Book the hotel well in advance: the hotels in London are generally old, bad and expensive. The longer you wait to book, the more likely it is that a badly located or inconvenient hotel will touch you.
Visit the Borough Market on Thursday or Friday. On Saturdays it becomes really unbearable..
Match the trip with the first Thursday of the month: it's Firts Thursday, the night the galleries open exhibitions and open their doors to the public for free.