Three things that you need to get right to have really good skis
The three big factors are ski selection, structure, and wax. Sometimes one of these factors plays a more influential role than the others, but in general, in order to have decent skis, you can't miss on any of the three. If for example the snow is very dry and you have great skis and wax, but a "wet" grind, you're not going to have really good skis. If the snow is very wet and you have great structure and wax, but the skis are wrong, you're not going to have really good skis.
Ski selection is too complicated to describe in a brief piece like this. For skating, the skis need to match the conditions. This means, not just softness of tips and tails and camber height, but also how much contact the skis have with the snow when they are weighted. Some skis have more and others have less. The best skis for cold dry slow conditions have more contact with the snow. The best skis for wetter (and dirty) conditions have less contact. For classic, things get even more complicated as the above apply as well as the need to get kick and keep the wax off the snow as much as possible. Generally your "wet" skis have a higher camber than your "dry" skis which matches the glide needs as well.
Most of us are relatively informed regarding structure. A good way to manage structure is to get a fine grind (cold) and then apply hand structure as needed.
Of course the properties of cold and warm waxes for example are radically different. They are good in what they are supposed to be good in and not so good in the the opposite conditions. Application method and technique also count for a lot.