By now you know where you're going, when you're off and where you're going to be heading to and maybe even booked your accommodation. But you will still need access to more money while you're away - there are souvenirs, entrance fees, local transport, meals, tips, coffee's, tea and scones, etc., etc. that you will need to pay for as you travel to all these incredible places you're planning to visit.
Ensure you have at least two different sources of funds with you on your travels - it can be very frustrating if you lose your one and only credit card. So make sure you have two cards kept in two different places, backup cash, Travellers Cheques (see comment below re: travellers cheques) or a source of funds that can be sent to you at short notice from back home (we prefer the 2 card approach - mind you we use debit cards with an overdraft option rather than credit cards - travelling on credit means you can't afford to travel). Make sure your card/s are Cirrus or Maestro affiliated and you will be able to draw out funds in any ATM anywhere in the world.
Always have some emergency cash money with you in US dollars, Japanese Yen or Euros - about US$500 should be sufficient to see you through if necessary.
Forget about Travellers cheques - they are an expensive way to carry and exchange money, many businesses today will NOT redeem them and too often the banks are closed when you need to cash some of them. But they are a very secure way of carrying money but are really not worth it.
ALWAYS use a money belt to secure your money and passport and make sure you wear it under your clothes - or buy a pouch that you can hang around your neck and under your shirt - keep it out of sight. They can be purchased at travel shops. It may be a bit difficult to get at your money but it is well worth the security they offer. DO NOT USE A BUM BAG! They can be taken from you in less than a second.
Some money saving ideas if on a budget Never change one currency for another in a third country. You will be slugged for the exchange fees twice over. Change US dollars for Indian Rupees in Singapore and they first; exchange your US Dollars into Singaporeans Dollars and slug you an exchange fee. Then they take those same Singaporean Dollars and exchange them into Indian Rupees and slug you another exchange fee - it ends up being very expensive for large exchange amounts. It is generally best to change currencies in your destination country (ie change your Australian Dollars into Japanese Yen in Japan).
Alcohol can be very expensive in some countries (like $12 for a glass of beer in some Scandanavian countries - not that cheap in the USofA either). Buy drinks in a supermarket or bottle shop and you can save a lot on money.
Wash clothes in the shower, wash basin or bath at your hotel and hang them up in the bedroom to dry. Using hotel or public laudromats can become expensive - if you can even find them.
Often places worth a visit can be free or have cut price days - check them out and get there when it's cheapest.
Some restaurants don't diplay their prices which can lead to gasps of dismay if you're not careful. Either go and find a place to eat that advertises the price or ask.
Some restaurants will charge you for sitting down (common in Italy and France) so check it out before you sit or be safe and stand and eat/drink at the bar.
Always use phone cards when using phones, especially when phoning overseas. Costs can be cut by upwards of 80% by using these cards. Find the cheapest for the country you will be calling the most - home?
Things are always cheaper in the countryside so don't hang about citys all the time. There are also wonderful places to go that are not Rome, LA, London, Tokyo or Berlin.
Buy food and clothes in markets as they are cheaper places to buy food than restaurants or even try a supermarket. Make up your own meals - try sitting on the bank of the Seine with a hunk of cheese and a French loaf you just bought at the local food market - blissful and cheap!
In poor countries it is safe to eat the local food! But make sure that it is either peelable fruit that YOU peal, fresh fruit (non-peelable) and vegetables that you have washed with bottled water or that the food is streaming hot - make sure you see it steaming as the heat will kill the germs that will cause you the most problems.