We have been going for several years. Had to go in the first week this year so we benefited from 2 for 1 tickets on the Mon/Tues (though the downside was that a number of shows were sold out in advance which I doubt would have been the case if they were full price).
We like to book a few events in advance so that we have a bit of structure otherwise it’s a bit overwhelming (would certainly be if it was your first visit). Then read the reviews as they come out (I’m subscribed to both the Fringe and The List emails).
I like comedy & we saw a couple of good ones, but seeing a variety of things is my preferred option - not just comedy but music, dance, theatre, circus etc. Also meeting up with friends in the pop up bars, having a couple of nice meals, exhibitions in the museums, guided walks etc etc.
There is lots of free non-ticketed comedy and that can often be for a reason (although you may chance on a good one). Also, bear in mind that, as the performers say, it’s free to get in but not to get out 
Weather was amazing this year as well so we were able to enjoy the outdoor spaces more, great to be wandering round in T shirts late at night.
I’m laughing at the thought of fewer shows - it’s now our tradition to say every year as we’re going home “we should have come for longer”