The information provided beneath the image says the shutter speed/exposure time was 25 seconds and the aperture was f5.6. ISO was set to 100.
There is a slight lack of sharpness to the shot, I agree. However, it's not bothersome to me unless I try to tell myself photography is all about sharp edges in the shot. If this is the kit lens for the Nikon, then I'd say the camera was more at fault than the photographer. And that, then, can only really be improved by spending more money. Therefore, I would ask, just how sharp does any photo need to be? I'm rather of the opinion that "sharpness" is a useful justification for buying more expensive gear and setting yourself apart from the rest by what you own not what you can do with what you have.
But, gee, this is Italy we're talking about. A shot of Vicenza! If you're options are being in Italy or buying a better lens, take the trip and then sharpen things up in post production. You could give us a photo of Italy almost completely out of focus and I'd still be enchanted. And the ski photos are quite exceptional IMO. Very nice work and they indicate you are learning your camera well.
On the op shot, if you don't own a tripod, then shots such as this are going to be difficult. Selecting 100 ISO only makes them more difficult to capture hand held. Therefore, if you want to increase the sharpness (and you are not using a kit lens), then you should decide which is more important, getting the shot hand held or increasing the ISO sensitivity. The thing is, though, this type of shot really does need a steady camera which can't be accomplished by hand holding the camera for several seconds.
There's a general haze to the image outside of the central objects. That, IMO, is the strongest detractor of this shot. Not sure why it's there or how exactly to correct it on a long shutter speed shot like this. I would think it could be corrected though in post production. No?