Posted: 13/03/2017 at 15:38
I don't think it is particularly something you are doing wrong - the most likely reason is that you don't have frogs nearby. Do your neighbours have ponds with frogs ?
Annoying it may be but you can't make wildlife visit your garden at the drop of a hat. If there are "spare" frogs in the vicinity, I'd have expected some to be looking at your pond by now. Frogs have suffered depletion in numbers in the last few years but have you thought about contacting your local Wildlife Trust and asking them about the population for your specific area.
All is not lost tho - if you have Toads and your pond is to their liking, you could get lucky. They tend to breed earlier than Frogs. Or perhaps Newts ? Again, a word with the Wildlife people may give you a clue as to what you can expect/ encourage to your pond.