1. Air Fares
Look harder. Be diligent. There is always air fares promotion from time to time. You just need to be there to book in time! Hence have an idea of when you are going so that you can straight away jump into those juicy promotions. Qantas now has a return fare promotion to Tokyo (Haneda) at A$1,001. Supposed to end 22 June 2016 but based on my personal experience. The ending dates can changed. I was sitting on an air fare promotion to Singapore, thinking that I still have time to decide but they end the promotion earlier! We ended up paying A$500 extra for a pair of return tickets.
Airlines typically will release a chart showing the varying fare pricing for the next 1 year. Usually the fares will be higher during occasions like special festivals or school holidays etc. So try to avoid these periods for best prices.
2. Accommodation
Accommodation is usually the most costly item in the travel budget unless some of the lucky folks have friends or families they can bunk in with. Good thing is that with so many accommodation booking sites, travellers have a lot of choices to choose from. Not to mention that competition drives down prices.
I did a comparison across various hotel booking sites and I generally find that Agoda offers the lowest prices for the same selection. Hence I usually book through Agoda. I also like the fact that you can convert the prices to the currency in which your credit card is denominated in so you know exactly how much you are paying, This is where currency also comes into place. See Point 3 below.
As some of you may recall that I usually stay at Toyoko Inn I guess these days there are more choices. Saw some good offers on Agoda. Due to the high property prices in Tokyo, the hotel prices aren't cheap. If you are a family with young kids, you might have problems finding a hotel that suits your budget and yet provides a room that is big enough to cater to you and your kids. Airbnb is a good option in such cases. However, please be realistic in your expectation. Most housing in Tokyo won't be as spacey as the houses in Australia.
3. Currency
I briefly mentioned earlier that AUD has been depreciating, this makes me conscious of the exchange rates. Hence it will be wise to monitor the trend and make the currency conversion at a good rate or at least at the rate that you are comfortable with (I mean we all are not forex gurus - at least I'm not. I have not managed to buy my foreign currencies at the lowest but I'm good with the rates that I paid). Estimated your rough expenditure beforehand so that you will know how much to exchange. Remember to consider if your accomodation will be paid in cash or credit cards. If you are paying for your accomodation upfront, it's good to time your booking when the exchange rate is good. There are many forex sites that you can use to monitor exchange rates. The one that usually use is Oanda (https://www.oanda.com/currency/live-exchange-rates/)