These are a few signals that can help you differentiate flattery from genuine compliment.
- Pay attention to their style of talking. Whenever someone is using flattery with a certain degree of subtlety, he/she is likely to appear and sound artificial. Although detecting if someone is lying or is telling the truth is not a easy business, however, if you have done a good deal of interaction with them then you can easily make notice in their facial expression and voice tonality when they speak the truth vs when they indulge in talking things that are completely or partially false
- Although in the initial stages it becomes slightly difficult to detect if someone is using flattery as a means to get his/her job done through you, however, if you know this person for quite some time then you can carefully observe and notice if in the past they used the same strategy of talking goody good things about you on your face or in public and then asking for some heavy favors from you later. If you have had such an experience multiple times, then you can assume that the great things he/she talks about you is not a compliment but flattery
- At times it may also happen that people who are jealous of you may upfrontly and excessively appreciate you, so that you can climb up the hill of ego and pride and once they notice you on the top of the that hill, they will then execute their next move to push you down (This may sound like some sort of dirty politics, but I have seen many people who do indulge in such strategies and aim at defeating fellow employees who are in the race to the next promotion)
- Finally, whenever you receive a compliment hold on and think if it is true and that if this person who is complimenting you knows you on a personal front. If you find that the compliment sounds too heavy (& untrue) then you better stay grounded and be on a alert regarding that individual