I often use my travels as research. Some of these places I've visited I'll never get the chance to visit again, so I was very organised about it. Consider creating your own guide-book (I always do).
Get a modern map of the area where your novel is set. Then search the internet (or the library, in some cases it's easier) for a map of the area at the time of your story. Analyse the differences. You should visit all the areas that are still as they were (or as much as possible). If you can find old photos, take them with you.
If you do create a guide-book, include both maps and then research details about the area, using the old photos as illustration. When I visited Lyon, France, I was able to walk all the old streets following my guide and noticing all the little nooks and secrets I'd have otherwise missed.
While you are walking through the streets in the actual place, plan to take one round carefully studying your notes and comparing them to the reality you see. Add more notes (leave space in your guide-book for handwritten notes) and take plenty of photos (start with a wide shot then keep zooming in into little details) Think of it as a photo-story. Then, go through the same streets with both the guide-book and the camera in your bag. Just close your eyes and try to put yourself in the shoes of one or two characters, then walk up and down and try to imagine yourself living there.
The first walk-through has a technical objective: capture the reality as accurately as possible. The second one has a sensual objective: let your senses command you and soak in as much of the ambience as possible.
If it's a rural or forested area, do the same. Find out what crops were common at the time, machinery (if any), animals, weather... Search for old photos, too. If possible, try to visit the places in those old photos, but, in the countryside, it's easy to look at a photo of an agricultural field and extrapolate to other fields. They were rarely that different.
Again, find old photos of the area. They will likely star anonymous people, but it's easy to start imagining life stories for them. See if your characters could be in a similar photo (women getting water from the fountain, school children around the teacher, field workers standing by their oxen...). As you walk the area, always take a time to look around and imagine the people from the photos going up and down the roads. Then turn those ghosts into your characters.
When possible, sit and watch the people as they go about their lives. Take particular attention to old people: they're the ones who will still echo the traditions and habits of the past. If possible, listen to how they talk: expressions, sayings, gestures... everything is useful. If you see two old women chatting and one shows herself to be merry, try to imagine her as a young girl. Young people are the same in every time: they want to have fun, be with their friends, flirt with their flames... (yeah, I know, the way one flirts changed enormously, but the wish to do so is intemporal).
Think with your senses... even if it's not enough.
Research the food, the climate, the terrain, the building materials... and then compare what you see to your research. Ideally, you would visit the place at least four times in a year, so that you get a feel for what it's like in summer, winter, fall and spring. In the very least, see the way the sun illuminates the area throughout the day. Try to see how visible the stars and the moon are. If the area is now well illuminated at night, but it wasn't before, go to the nearest countryside and take a good look at the sky.
Imagine yourself walking the dark streets... or buy an old lantern and walk the countryside roads to get a feel for what it's like.
While researching, try to look for accounts of people who lived there. There are diaries of authors, travel journals, and there are also ethnographic reports. The latter in particular can reveal small details of people's lives at the time that will enrich your novel. You'll discover the difference in food between poor people, fairly well-off people and rich people. You'll find out about expectations of the time for behaviour. You'll discover old-time medicines and superstitions. When talking to people, ask about the weather, the houses, the medicine, doctors, everything you can think of. If you interview a particular chatty person, let them talk freely: they may end up mentioning things you haven't thought of.
While out there, look around and try to picture what you learnt in your surroundings. When you see a shepherd with a dozen goats, remember the accounts of herds with thousands of goats swarming the roads and the shepherd dogs running or yawning relaxedly by the side.
If your story is set in the countryside and you're not familiar with the rural world, stop to watch as people go about their lives and work. If you see the aforementioned shepherd, look at how his animals behave or start a conversation and ask the shepherd about his work, about the animals... you'll discover things that no book can tell you (e.g., I discovered from a family who raised cows that cows will eat kittens if they find them nearby. This can become part of the novel if you need a scene of a mother telling off her child: a young child is crying her heart out over the little kittens while the mother grumbles she shouldn't have taken the poor things to where the cows were, what was she expecting!).
Some information is easier to collect on the spot. If the area in question is a small town, there will likely be some books in the local library with documents of the recent past that you won't find elsewhere. If appropriate, contact the local museum (even hamlets sometimes have one) and see if you can arrange an interview with someone.
Once I visited a small interior city and visited its library. It was set in the building of an old convent and the staff was so mistified with the idea of someone coming in just to see the building and learn about its past, that I ended up having every staff member becoming a private guide, showing me all the space, sharing a few stories and offering all the help I might want researching documents and even facilitating access to old documents which are usually unavailable and which bureaucracy forced people to wait for days between request and consultation.
Locate any and every museum that depicts life in the period you want, whether it's an actual museum or simply the house of a famour person which was turned into a time-capsule. If such museums only exist in neighbouring towns, visit them nonetheless. These places are invaluable for one to imagine what real life was like.
5. What to document
If you create your own guide-book, you can use it as a place to take notes and even correct or expand on previous research. When you interview (or just chat with) people, always get their name and contact. Later on, you may want to keep in touch with them, not to mention you may make some very interesting friendships.
Take plenty of photos. If possible, keep a diary of the photos so that you won't forget a particular detail concerning them. Just jot down the time, take your photos and make some notes (and always make sure the camera has the correct time stamp and, if possible, will add coordinates to the photo meta-data).
Try every traditional food and drink, take photos and write down a description of the taste, smell and texture. Remember that a lot of popular dishes that are now touristy were once all a poor person could eat. A traditional meat soup that now includes plenty of meat and a variety of vegetables might have been nothing more than a pot of water with a bone thrown in and some old leaves of cabbage for some families. Favour local or family-run restaurants and bars and, when possible, ask about the roots of the dishes and drinks.
6. Time Constraints
You may have too little time for all I mention above. Look at what you want to write and decide what is the most important, then give priority to that.
You may find yourself running from here to there in order to achieve all your targets, but force yourself to stop and take a deep breath, to forget about your hurry and simply enjoy five minutes of relaxation. That will help you feel the place in a different way.
If you already have a well-defined plot, try to go over all the places where your story is set.
7. Final Thoughts
Much of this research will transpire into your novel in two different ways: some things may impact the plot, most will simply lay in the background creating the right feel.
For example, you may discover interesting details about 'women of virtue' which may have a character decide to act in a way that seriously impacts the plot... or you may simply have two characters walking past a group of children making dolls out of red poppies.
While you are creating your own guide-book, you'll be ammassing plenty of info. While visiting the place, you should first let your senses 'feel' what your mind has studied and assimilated, and then you should try to imagine your story taking place in loco.
Oh, and you should have fun while doing all of it. If possible, find a friend willing to be your side-kick, but make sure they'll be willing to put up with your research. Otherwise, fly solo and make the best of it.