What is the weight budget of a fully loaded A380?
These weights are all based on the maximum an aircraft will ever see. The maximum allowed weight of passengers (+luggage) and cargo (called payload weight) is the difference between the Operational empty weight (about 270,000 kg) and the Zero fuel weight (361,000 kg). This means the payload weight is about 91,000 kg. The passenger and crew weight can be estimated by the following numbers:


175 lbs per pax + 30 lbs of baggage for short medium range distance (or 40 lbs for long range)
175 lbs per crew member + 30 lbs of baggage$^1$


So let's say that (for easier calculations) the average passenger + luggage weight is 100 kg.
When we assume 530 passengers and 25 crew, then the weight would be $555\times100=55,000kg$. That leaves 36,000 kg for cargo.
All the weights listed are, of course, maximum weights. That means that an aircraft in general does not meet these values.

The maximum fuel weight is the difference between maximum ramp weight and zero fuel weight (which is $562,000-361,000=201,000kg$). About 2,000 kg is taken for the time the engines are running while the aircraft did not yet take of (for taxiing etc). This is the difference between maximum ramp weight and MTOW.

The amount of fuel varies so much per flight that I really can't say anything about it. It depends on the air pressure in the flight path (aircraft choose their routes depending on that, for a faster flight), weather along the route, and much more. For quite a good overview I suggest for you to read this Wikipedia page.

I hope I answered your question sufficiently.

$^1$ Source: Jan Roskam, Airplane design, Part I: Preliminary Sizing of Airplanes (1985)