1. If you already know what Country region or city you want, then skip to 3) below

2. If you DON’T already know what continent, regions, countries or cities you want, follow these suggestions:
    a) Create a simple Potential Site LIST, written or computer, with columns for: 
         1) countries, continents or regions, 
         2) cities,
         3) Travel Bud sites or experiences you have been exposed to OR dreamed of.  
                 Your mind is filled with your own Travel Buds, if you look for them.
                                           Anecdote:  some of my Travel Buds:
      Audrey Hepburn’s “Two for the Road’ romantic European travel movie; European travels. 
      Russel Crowe’s “Gladiator's Coliseum; my Rome visits.
      Brad Pitt’s “Seven Years in Tibet.”; triggered 3 months in China .
      Art History class: exposed Athen’s Parthenon's intentional optical illusion of slightly
              bowed steps & bulging columns. 

    b) Watch some TV or Netflix travel shows:    
          “50 of the Best Travel-ish Shows to Watch”: https://www.going.com/guides/best-travel-shows

    c) Explore some Travel blogs. (Don’t search “Travel websites” yet cuz mostly Cruise
           company advertisements)
               “FeedSpot”: ”100 Best Travel Blogs To Read”: https://travel.feedspot.com/travel_blogs/

As you build your list, some country, region, city, sites & activities
will truly speak to your interest.
It will happen. Trust me.

3. Confirm your continuing interest of your lists’s Travel Buds with Google Search your list to. You may have changed your opinions. eliminating those that you have less interest in.

4. Google Search your desired countries & cities for all tourist sights & experiences that you didn’t know about … that excite you enough to add to your list.

5. Prioritize your FULL ‘List’s of most desired sights & activities (maybe with colored circled numbers next to site or activity.

     TIP: I use a different color, or circled numbers to left of list items.
            Examples: 
                Tier 1: (1) Colosseum, Roman Forum, Pantheon, (2) Vatican, St Peter’s Basilica,
                        Trevi Fountain & Spanish Steps.
                Tier 2: Baths of Caracalla, Trastevere neighborhood, Galleria Borghese museum,
                       (3) Michelangelo’s Piazza del Campidoglio, Basilica di Santa Maria Maggiore,
                       Basilica di San Clemente and so on.

You NOW have a condensed checklist for screening through Cruise company internet Shore Excursions offerings

6. Search usual cruise ship ports to discover sites & activities there or accessible from there.
    Example: 
        Cadiz, Spain is a main cruise ship port with a few sites of interest: 1) Old Town (El Pópulo)
            , 2) old city walls and gates, 3) Cadiz Cathedral (Catedral de Cádiz), 4) Plaza de San
            Juan de Dios, 5) Roman Theatre, 6) Museo de Cádiz, 7) Tavira Watch Tower, &
            8) Santa Catalina Castle. 

        Accessible from Cadiz: 1) Seville, 2) Jerez de la Frontera, 3) Ronda’s Puente Nuevo,
            4) Arcos de la Frontera, 5) Gibraltar, 6) Costa de la Luz, 7) Tarifa, 8) Roman Theater,
            and 9) Museum of Cadiz.

7. Choose your ideal Cruise Company quality level & style the cruise package that includes your top available sites & experiences.  Note: maybe only 1 or 2 sites far from Cadiz because usually not enough time for multiple sites & activities unless close together. 

Cruise Categories: Luxury levels to Adventure, etc.

Before you wade into the gargantuan pool of all available cruise packages, select the cruise company style that most suits you and, THEN, focus 1^st on their Shore Excursions offerings.