Maps in ETQW and the way of executing operations are the most debatable issues in the whole game. The descriptions you'll find on next pages - except listing main and secondary objectives - are written to show the most common players' behaviours and how to react to them.
Moreover, map presentations say about the recommended class structure of the team. It would surely help in choosing own functions. If we assume that the best combination is 7 soldiers / 7 medics / 2 spies, then our own function should bring the general proportion of classes in the team closer to the one presented above.
There are a few typical actions, which just should be performed to improve the way the team works. These are, for example, deploying radars and anti-artillery systems each time the frontline moves. Descriptions of maps remind of such actions in cases when they're particularly important and necessary.
70% of success is the ability of working with other players and doing own job scrupulously. 15% of success is the accuracy (including shots fired from vehicles), 10% of success is the speed with which we move and the remaining 5% is a thorough acquaintance of maps, particularly these complicated systems of corridors, in which we can usually see the last objective of the whole operation.