In general, a practical goal is to identify the decade
, never mind the year
In modern photochromes (cards like the ones you've shown), consider the size.
In the US, you'll find both 3x5 and 4x6 photochromes. Different publishers switched at different times.
Also, look at the quality. The early photochromes (especially in the US) were bloody awful: the color registration was so poor that the early cards (eg 1950s 3x5s) can be painful to look at.
But European publishers switched to photochrome much later, so these will almost always be 4x6, and almost always be of a higher quality.
My guess? Your cards are probably 1970s-1980s.
Wanna do better?
1) The number of digits in the telephone number & the postal code in the publisher's imprint will set reliably hard limits on the date range.
... you will find many publishers listed in the MPC database with some indication of the years in which they operated ... but no database is perfect
3) Lastly, of course, there's content. Do a Google image search on the subject - or use Google Earth, if appropriate - and use the buildings or features that are not
in your card's image to help set the date.
Sometimes, you can get lucky with details like scaffolding on an historic church ... if you can find out when they were sandblasting that exterior, Bob's your uncle.
And, sometimes, you can get stupid-lucky because a well-documented skyline is constantly changing. Don't let the sepia tones in the postcard (below) fool you. The image includes the New York Merchandise Mart, completed in 1974, and a building that I'm pretty sure is the not-yet-complete 3 Park Avenue, completed in 1975.