Old French Chef Rule of Thumb: 'if you do not like doing it, you will never be good at it or make good results' (OK, I just made it up).
The essence of really good petit fours is someone who genuinely enjoys doing it and will, without concious thought, go the extra mile to make it good no matter what anyone says or may suggest. I say this as someone who has made more than my share, both personally and professionally.
If you wish to make knock-your-socks-off petit fours, you have to be someone who loves petit fours at least as strong as knock-your-socks-off. Personally, I find them much more trouble than they are worth or worth worrying about. Sadly, there is no magic bullet that will impress.
I would like to turn your question on its head: why do you need them? Will not a truly remarkable champagne or rose do? How about antojitos? How about tapas? How about sushi? Are these a dessert substitute, or appetizers? Are there any alternatives? Is your choice of 'petit fours' cast in concrete by a customer or chef? Are they part of a tasting menu or tasting buffet? Is it part of a demonstration or food educational event?