In thermodynamical cycles...

it's usual to find the difference of the enthalpy of two points of the cycle to find the heat transfered...
How can i find the enthalpy? sometimes the solutions just place the value like its taken from a table.. help me please...
thanks
(for example the rankine cycle)

For most commonly used chemicals (small hydrocarbons, refrigerants, basic alcohols etc.), you can find charts and tables online which will give properties such as enthalpy, entropy, temperature and pressure for different states.

You could also use a range of equations of state which correlate different state properties to eachother. They may also be more versatile if you are needing enthalpy data on something that is not so common, such as a particular mixture of chemicals.

There are charts and tables that show enthalpy properties, pressures and temperatures for all major
gasses.

Try googling them............