Let me be clear: as a rule, I am against over-organizing trips in general. The pressure to accomplish it all can greatly overshadow any chance for spontaneity which is where some of your best travel moments can happen. However, it's a good idea to have a basic idea of how you want your trip to flow in order to avoid scrambling at the end to fit it all in or, worse yet, missing out on something.
Step 1: Figure Out Your Must-Dos
Think of your "must-dos" as the foundation of your trip. Decide what days you want to accomplish each of them and then you can build the rest of your time around them. These are going to be the places and experiences that you've dreamed about the most when you think about the place you're visiting. Want to make sure you get that photo op of you holding up the Leaning Tower of Pisa? Add it to the list. Need to do the sewer tour under the streets of Paris (for the record, I do NOT recommend this! I'm still gagging...)? Add it to the list too!
Important tip: be sure to research these places, experiences, and tours first, as they tend to be touristy things like museums or points of interest that have operating hours and certain days of the week in which they are closed completely or do not operate all together. Also have a look at the weather when you arrive. You may need to do your Tuesday plan on Thursday because the weather will be better for it.
Years ago, I was guilty of not researching out a day trip to Normandy with my parents when they came to visit me in Paris because I had already been and thought I knew how to map it all out. We spent so much time at the first few spots and had left the American Cemetery for the last activity of the day. To our horror, we got there just as the gates were closing. Luckily, I had learned of a secret entrance on a prior trip there, so we got ourselves inside, but had we not been able to do this, my history buff dad would have been incredibly disappointed.
Step 2: Regulate Your Activity
If you decide to do a walking tour one day, then the following day you're going to want to do something with more low-key activity. You may be thinking "whatever, I'm fit and I can handle it!" and you're probably right, however due to the fact that you're most likely still combating jet lag or just travel fatigue in general whether you realize it or not, you'll end the day much earlier than you should and find yourself in bed while the locals are just heading out for dinner.
I'm not recommending that you become immobile the day after spending a lot of time on your feet, but if you had planned on fitting in a trip to the hotel spa, then schedule it for the following morning to restore your energy levels. Afterwards, head out for lunch at a sidewalk cafe, order some wine, and do some serious people watching. After your eyes and stomach have had their fill, hit the pavement once again and do some exploring! Your body and brain will be grateful for the break and ready to roll again.
Step 3: Plan to Hit the Town
Tourists do most of their exploring during the day up until dinner time, but places change and take on a new light once it gets dark. Plan to hit the town at least one night on your trip and see where it takes you. Start somewhere for cocktails, sit down for dinner at that new spot you read about, and then factor in some after dinner drinks or dancing. Integrating yourself into the local scene is a great way to learn more about the city and allows you to forget that you're a tourist for a minute and leaves you feeling like you just might be a resident (which is a pretty cool feeling).
Step 4: Take a Day Trip
The hustle and bustle of a city can be exhausting even for those who thrive off of that energy. Taking a day trip away from the city is a great way to feel like you are really getting a well-rounded experience of your destination.
One of the best and worst things about cities around the world is that they can offer you the creature comforts of home should you openly seek them out. Starbucks is a perfect example of this. You can be thousands of miles away from home, but you can still have your grande, iced, sugar-free, vanilla latte with soy milk. Step outside the city, take Barcelona for example, and head out into Catalonia to visit the cava wineries. If you want to grab some coffee along the way in one of the small villages, you're forced to visit a small cafe and drink it how the Spaniards take their coffee. Now you've got a great memory and story about that time you were trying to assimilate into Spanish culture, were failing miserably at trying to order a coffee in Spanish, and an old man took you under his wing and showed you what to order and it turned out to be the best cup of coffee you've ever had. In return, you introduced him to the doggy ear filter on Snapchat when you took a selfie with him and you both had a good chuckle. If you had gone to Starbucks all you would have gotten was your name spelled wrong on your cup.
I'll get off my coffee soap box now. But seriously, there are some really cool things to see usually just outside of a major city. In Europe and Asia, high speed trains allow you to cover much more distance in a day than standard trains, enabling you to reach some pretty incredible places. If you're staying in Paris, hop on the TGV to see the magnificent castles of the Loire Valley or to Reims to visit the famous champagne houses of Veuve Clicquot and Tattinger. Travel is about immersion in culture and a day trip will certainly help you to do that!
Step 5: Leave Blank Space
Now that Taylor Swift song is in my head. But for real, leaving pockets of blank space will allow for that spontaneity I referenced earlier and also for you to revisit certain areas or places that you loved. I tend to leave this space for the end of a trip. By that point, you will have a good sense of what your favorite parts of your destination were and what activities you had the most fun doing. This open time will allow you to repeat something or even swing by that cute shop that was closed when you walked by the other day.
Once you've nailed down the pattern for your trip, the days will have a natural flow to them and you won't begin every day saying "what should we do today?". Travel can be stressful, but knowing in what direction you are heading each day will allow you to truly be in the moment and appreciate your surroundings.