These are all great. Unfortunately I disagree on the reliability of Quora User's "wear and tear on that yellow line" tip. This may well apply to some stations however I have not been able to tell any differences. read more
You can get a special, TFL-branded "Baby on board" badge for free by emailing them – it can help counter the awkwardness of asking people to give up a seat (although the rest is up to the good manners of Londoners, obviously). read more
According to TFL, If you *beep in* into the Underground at 7pm instead of 6.59pm on the tube on any given day, you will save up to 70p between Zone 1 and 2 and 60p if you're travelling between Zone 1 and 3. read more