I permit myself to suggest that who wants to take a ride in a gondola should take into preference the beauty and the elegance of the boats, attentively observing that she is completely clean and well-kept.
By doing this, you will put into motion the natural improvement of those few boats still in circulation which are in a pitiful state and take advantage of being amongst the many boats that are for hire.
The choice of the gondolier should be secondary to the choice of the gondola, but nevertheless, there are those prefer a younger and more attractive gondolier and those who prefer an older, more experienced gondolier who can help them obtain a better understanding of the perculiarities and the different aspects of Venice, as well as her problems.
It is good to know that it is extremely difficult is not almost impossible to know the movements of the gondoliers, so if you find one that takes your fancy, take immediately advantage of your ride in the gondola; if not, at least return later on the same day to the place that you had seen him, because the day after he will not be there.
Just like the stars that seem to be randomly dispersed in the sky, so too do the gondoliers seem to be randomly dispersed around Venice.
And just as the stars are grouped in constellations, so do the barcarolles move in a predetermined order with the difference that while astrolabs exist to assist with the identification of constelations, there is no instrument that can help you find a gondolier amongst the maze of canals except for the direct knowledge of the territory in which they operate.
Therefore, the easiest method in tracking down your gondolier, is asking someone who knows the ground...