I cannot give you any tips...I have never caught a mahi mahi.
What I can tell you, is they grow fast...a 2 year old is big and I mean big! Because they grow so fast they eat a lot and eat it fast...They are pelagic at the sharp end of the stick. (pelagic means hunters or surface hunters). They strike hard and fast. They are one of the fastest and most aggressive pelagic fish in the ocean.
They like it fast and loud...A very fast retrieved popper should do the trick. That would be my first choice.
itsaboat mate...Life is just a boat and then ya marry one !