From A Guide to the Study and Use of Military History By John E. Jessup, p66, on Art of War:

'Machiavelli looked to the classics for inspiration and most of his ideas on training, tactics, organization, and command are little more than attempts to adapt practices described by Livy, Polybius and Vegetius to conditions prevailing in the fifteenth century.'

That being said, George Bull's introduction to The Prince suggests that it was his travels as a diplomat between 1498 and 1512 that reinforced his ideas concerning the use of citizen militias as opposed to unreliable mercenary bands. In this sense at least, some of his ideas could well have been based on his own experiences during the period.