how do i travel the world cheaper? i know traveling Europe by train is,but how about the world? Thank you?

I want to travel to these major cities:
Dublin
Rome & Milan
Paris, Perth & Sydney
New York, Hong kong & Tokyo
Rio de Jeneiro, Barcelona & Madrid
Ottawa, Vancouver & Singapore

I also want to go to Cuba, Venezuela & Egypt
Basically all over the world! By dmofokenggood luck unless you grow wings
I have friends with Sailboats. Nothing fancy, heck, they 38-48 footers. They go to many places in these boats. Another thing you can do, is find like a Pen Pal service on the Inet and make friends with people in the places you want to visit. Then when you go they will know where the good cheap places to stay are, away from the Tourist traps. AND, some even let you stay at their home, if, there room for you. But, you need to do the same should they ever want to visit. It really is cool and I know it can be done.
The cheapest way to travel is the same way the locals travel. You should read books by travel writers--Paul Theroux, Bill Bryson, Eric Newby, etc.--to learn from their successes, as well as their mistakes.

For example, many locals travel the Mediterranean via ferryboat, the lowest class available (usually just a seat) and the prices are considerably less than any other method of travel. Likewise, bus travel throughout parts of Africa and Asia is very common. There are the A/C tourist buses, and there are the local buses, no A/C, no upholstered seats, but plenty of local color for a few cents.

In terms of housing and accomodation, again, look for where the locals stay. A hotel with A/C and private bath is going to cost you more. Another option would be to stay with a family in a community; many times a middle-class family will rent out a spare bedroom to bring in extra income. My husband went to Cuba and stayed for a week in a family home, at a total cost of $45 US for the week.

If you have any mechanical or technical skills you may be able to barter these in exchange for food or accomodation. Travel light but bring plenty of trinkets--cassette tapes with pop music are especially popular--to barter with.

Good luck, and with a lot of research on the internet, you should have an exciting adventure.