I usually connect so earlier European arrivals are better. Sometimes hotels have early arrival options where you can pay to get in to your hotel early. It's usually not a great deal, but sometimes it is.

Sometimes I store the bags in the hotel and go to breakfast, or visit a tourist attraction. Sometimes I investigate if there is a full service gym nearby where I can get a work out in, and maybe a sauna, steam room, and definitely a shower. That will usually wake me up and make me feel better. Then I go have lunch somewhere and eventually end up back at the hotel. Sometimes the hotel has a gym and a shower/sauna/steamroom that they will let you use.

If I know I am going to have time to kill before checking in, I make sure that I investigate things to do in the area and find a place to have a nice lunch. It's not ideal, but it beats sitting in the lobby in a coma or wandering around feeling miserable.