Must-Do's on Royal Caribbean Harmony of the Seas
 

We're taking a cruise on R.C. Harmony of the Seas in August. We've never been on the ship, but it looks great! It seems like there's a lot to do that's included in the price of the ticket, but I see that there are some additional options for an extra fee. Are any of these really amazing, or should we just stick with the free stuff?
Related: Are the water shows and theater nights an added cost, and are they good? Do we need to get tickets to these in advance? (and how far in advance?)

Your cruise should have a FB site as well as a forum on cruisecritic.com. On both, you will find fellow travelers, even some who have been on the ship, who can answer specific questions about that specific ship and that specific itinerary. There is certainly a Royal Caribbean website for your cruise/ship to find information about activities and the cost.
If there is something you really want, I would book it right away. Popular actives can sell out.

Do you have kids? If so, check out their activities, hours, etc. Sign them up now to avoid lines and to have them meet other kids right away. Kids tend to meet and pair up with others at some kind of initial event the very first day. You don’t want yours to be left out.

On FB, there are dozens of groups for Harmony of the Seas. There are three for August: the 1st, 14th and 21st. They are private, so you do have to join.

When we were on the Oasis, a sister ship the water shows and theater were free.
I don't think we had to reserve anything but better double check.
Most ships theaters are first come first serve.

Thank you for this information!

I'll check those out. Thank you!