Last October we did a 5-night out of Miami on the Dream as a 50+ adult couple, and we had 4 other adult couples join us. We had the BEST time and they are all still talking about it, despite some not even being Disney people.
We all dressed up for Pirate night and HotHS, entered the adult costume contest, spent countless hours at the adults only pool, hit the adult clubs at night for the evening entertainment, attended several trivia events and happy hours, did the silent dance party, did a few drinking events around the ship (not everybody, but a few did and enjoyed them) and created some super fun memories. This year we discussed doing another group cruise on another line, but our thoughts were if the line wasn't Disney it would be geared more for all adults and the adult areas might be more crowded. Our only complaint was that the food and the dining service were WAY below par (this was our 5th
Disney cruise, but first for most of the others so we know what it CAN and SHOULD be) but we had so much fun that it was just something to laugh about later.
I highly recommend it. We are still thinking of doing one again this year, likely on Disney.
Edited to add: I see you are asking for tips...definitely don't miss the trivia if you are into that. We showed up a little early each time, grabbed food from one of the counter service areas to snack on (for free) and enjoyed it. If you do enjoy some evening cocktails, find out where the happy hours are and what times and hit those. There is also usually evening food/buffets near the adults only areas...don't miss those, some were good some were just okay. We loved all of the adult shows and entertainment, nothing was every terrible long and try to participate...usually at least one member of our group was willing to participate in stuff or try to and it made it that much more fun. The adults only area pools are great for hanging out during the day, we met some great people there. We went to the upper deck in the evening to see the fireworks. All in all, just HAVE FUN!