Expers I am not able to arrange the elements or atoms or species in correct order from given set of options when it comes to me, and ask for ionization enthalpy, electron gain enthalpy, or electronegativity or any sort of other trend.
I have read the concepts of above topics thoroughly but still getting wrong answers.
What requisites I need, or what precautions I should take to have a better understanding and to get right answer in one go?

Dear Student,

You must be thorough with the concepts in order to answer such questions.
For eg. in ionisation enthalpy questions you must be know the trend and the reason behind the trend and try to correlate all the concepts.
Ionisation energy increases on going from left to right across a period. This is due to decrease in the size of atom on going from left to right which is the result of increasing effective nuclear charge. When we go across a period, the number of shells remains same and electrons are being added, therefore, effective nuclear charge increases and size decreases. When we go from top to bottom in a group, ionisation energy decreases because of the increase in size which is due to decrease in effective nuclear charge.
The trend for electron affinity and electronegativity is just the opposite.