1) Get an Oyster card right away. It’s £5 and you can top it up for any amount you would like (don’t be fooled by the options that are given in increments of 5 in the machine).
2) Take buses EVERYWHERE. You can generally get from any point in the city to another with a single bus + a 10–15 minute walk. It’s like a hop-on/hop-off tour for a fraction of the cost. It’s slower than the tube, yes, but you’re on vacation. You’ve got nowhere to be.
3) The best phone plan to get in London is the Pay-As-You-Go by Three. A sim-card will be .99p and will work with any unlocked phone (sim, micro-sim, nano-sim). An additional £20 will get you 12GB of data; £25 will get you unlimited data. The only drawback is that tethering is not allowed.
4) Book your London Eye tickets online for a specific 30-minute timeslot. This is the best option as it is the cheapest one that will allow you to skip the queue. If being tied down to a specific time-slot isn’t your thing, just get a “Fast-lane” ticket on the spot.
5) Avoid book stores. They are filled with amazing books and awesome souvenirs and everything seems so nice and lovely until you find yourself a day later with 10 books and doubts about whether your suitcase will weigh too much.
6) Feed squirels in the park. It’s fun and they’re hella cute.
7) The Pizza Hut on Lecister Square is way less crouded than the one at Oxford Circus.
8) If you’re stupid and decided to travel with cash instead of a card, the best place to exchange money is Thomas Exchange. There are many of them downtown and in the business area, but be prepared to stand in a line anywhere between 5 and 30 minutes.
9) When packing clothes focus on layered outfits. Shirt + Cardigan > Jumper.
10) £50/Day is a very comfortable spending budget. You can take it down to £25 if you have breakfast at home.