The easiest option when you land in a port you have never visited before is to take advantage of a ship excursion. These are convenient, safe and the best selection for most travelers. However, if you are capable, adventurous and independent you may want to explore a port on your own. The question becomes how and where to find the information you need to decide which option is right for you.
Over the years we have developed a laundry list of resources that we use to plan our day. If you are like me and need all the information you can get to make a decision you may spend time with all of them. Alternately you may find the answers you need after referring to just one or two.
My first stop is the excursions listed on the cruise website. This helps me to determine what the highlights are and I make a mental note of the cost for comparison purposes. Sometimes the ship excursions are the best option.
Then I check out my travel guides and videos. Whether you prefer Frommers’, Rick Steves, Lonely Planet or others there is much to be learned from the professionals. As well YouTube offers access to a number of excellent travel vloggers. I have found information on YouTube that is not available anywhere else and some of today’s vloggers offer high quality productions worthy of your time.
While online you can access the tourism sites for the cities you plan to visit. Make sure you are on the official page as it will offer the best recommendations and have up-to-date information on hours and costs. Downloadable maps and brochures are another advantageous option and can be found on most tourism webpages.
For further recommendations on the best to see and do check out Trip Advisor, Expedia and Viator. I akin this to asking my travel friends for ideas. If you do find an excursion you are interested in do a little more research to see if you can access the tour company directly. These sites do surcharge to book the excursions through them.
Private tour companies, such as Top Day Tours which serves a number of different countries in Europe, can provide alternative tours to those available on the ship. They are similarly priced and give you the option of small groups and custom itineraries.
Joining your roll call on Cruise Critic is another great option for getting recommendations. You can go to https://www.cruisecritic.com/rollcalls/, enter your ship and cruise dates and sign in to join a community of like minded travelers that will be on the ship with you. It is a great way to meet future friends and share the cost of excursions.
If you have a specific site, such as a museum or art gallery, you want to visit be sure to find their official website to book entry times and get advance tickets. Some sites are third party and surcharge the cost or do not offer as many options.
When the city we want to visit is the port where we dock it is much easier to arrange transportation into the historic core. Taxis are readily 
available and the cost can be shared with others. Be sure to agree to the rate in advance and comparison shop. At many ports a shuttle, which you arrange and pay for through the cruise ship, will transport passengers to and from the centre of town. From there we explore on our own, usually following a recommended walking tour from our travel guide or the tourism site, or one we have plotted ourselves in order to see our top sites in one day.
The more you travel the more adept you will get at researching a city and finding that very special event or site at which to spend your time. The longer you are in port the more you can plan to do, just be mindful of the time and when you need to be back on your ship. An adventurous and independent spirit may be your best travel guide.