It could do with some more diverse subjects.

Are you asking how you could improve your sales or something else?

Assuming it's about sales, I think you have images that appeal to a small-ish subset of buyers and where the agencies have a plentiful supply. As an example, I searched for istanbul mosque on SS and (photos only) there are over 46K results.

Another example where you have good search position in a smaller pool (about 3.5K) of photos is arabic pottery, but I expect the buyer pool is small.

Finding subject matter you can cover well is a good thing, but trying to appeal to more buyers means either a range of subjects or a more popular subject. Possibly there are less obviously glamorous subjects that might make useful stock - my home's septic system, hot water heater and such have provided good stock - no one will hang it on a wall, but lots of businesses need these subjects.

You're in Istanbul...

If you look at his profile, he's in Alexandria, Egypt - I assume there was a trip to Istanbul this Spring