1. Tripadvisor (https://www.tripadvisor.com/ ) is the best sight to plan for flights. Prices always seem to be a tad cheaper on this site, not to mention the daily notification I get for the place and time I am wanting to go.
2. If you know you are not traveling till the next year, try and shoot to buy your tickets on or after Labor Day, why you ask? Tickets seem to be at their cheapest. At this moment tickets are running $893 round trip so with Labor Day just around the corner ticket prices should drop like crazy. I am hoping to spend no more then $700 round trip apiece.
Though Tripadvisor also helps with booking a hotel and gives reviews and pictures taken by guests, I have decided to go with airbnb (https://www.airbnb.com/ ), it can be cheaper and the idea of having my own space sounds better then having a small space in a hotel where you still have to deal with a workers mood.
Now on to what I can tell you about what my research is telling me about London transportation.
Goahead and make it a priority to get a Oyster card (https://oyster.tfl.gov.uk/oyster/entry.do) either before or when you arrive. You can have it mailed directly to your house. You will get discounts on the Tube, buses, dockland light rail, and overground trains.