Apart from things you can't change like flights it depends on the kind of travelling you want to do, cost would differ between a backpacking type holiday, staying in hostels, using cheap public transport, whether you want more of a luxurious holiday with nice hotels and eating at nice restaurants or somewhere inbetween.
It could also make a difference which places (some more expensive than others) what you want to do there, whether you plan to work for part of it, how widely you want to travel, tourist attractions etc....
Can you give us more of an idea of your budget and plans.