Grand Theft Auto: Vice City

A wheelie can only be performed on a motorbike or a scooter by travelling on the rear wheel with the front wheel in the air. In order to perform a wheelie you need to accelerate by holding and then pull back on the to lift the front wheel off the ground. If you pull back to much you will fall off and if you don't pull back enough you won't lift the front wheel off the ground. As such, you need to find the sweet spot by modifying your speed. I found it best to keep the pulled all the way back and then tap to keep the front wheel at the perfect height.

Now that you now how to wheelie, you need to find a good motorbike to use. I suggest either the PCJ-600 or the Sanchez, both of which are very common in the game. Next you need a long and straight section to perform your wheelie. The two best locations are either the runway at Escobar International Airport in the South West corner of the map or Washington Beach on the Eastern side of the map. The beach has a lot of more room and is far longer than the runway, however, there are civilians and small ridges that can throw you off your bike. Choose whichever location you are most comfortable with and start performing those wheelies. When you land a wheelie, you will be notified of the distance as well as the length in time. Once you perform one that is at least 30 seconds in length, then the trophy will unlock.

The following video shows how to obtain the trophy using the Sanchez at the Washington Beach location: