Urban environments have become a favorite of mine over time- I find them a lot simpler to work with than natural environments because so much of them neatly fit within the basic rules of perspective Here are some examples from the only comic that has taken place exclusively in an urban environment (it's loosely based on Seattle)
The following are my biggest tips:
- It helps to practice and become very comfortable with the principles of perspective and how to locate things accurately with it. At least for 1 and 2 point perspective to start, but weaving in 3 (and beyond) as you become more comfortable can help add more dramatic shots to your arsenal!
Beyond just knowing how things recede to the vanishing points, it's also really handy to nail down how to scale objects in perspective. @rajillustration 's reply above goes into this. Beyond just locating one person though, a good next step to work on is using elements that you've already placed in order to place additional people or items all in scale to one another. For example, using the same example provided above, you can use the vanishing points to get more same-height people to scale in the foreground if you want to utilizing this will help you get the people looking like they fit into the backgrounds better because eveerything will be in scale relative to one another.
One of the things that immediately started making me feel better about my backgrounds (urban or otherwise) was just starting to actually research the type of place I was trying to draw and figure out what sorts of details belonged there. It takes more time to draw in details, of course, but I always felt like my backgrounds looked so empty, boring and lifeless when I was younger. taking the time to draw in the lines in the sidewalk, or some of the cobblestone texture, or the pedestrian crossing buttons on a traffic light pole, just adds so much to a background. Finding the balance between adding too little and too much takes practice though lol.
- this is like a half tip continuing from the above, but learn to prioritize. It's okay to go all out on some panels (establishing shots and the like) and "skimp" on others- it'll save you a lot of time and readers only look at each panel for a few seconds on average so there's no need to spend tons of time on each panel. This way you can save energy to flesh out the important panels where it counts without burning yourself out going ham on 5-7 panels every single page.
I hope this was helpful! Best of luck on your background journey
edit:
I forgot one of the big ones (regarding perspective rules)! The sooner you learn that any given scene might have several sets of vanishing points, the better! This took me so so long to figure out and wrap my head around lol. Regardless of whether you do 1 or 2 or whatever point perspective, the lines that go to the set of vanishing points that you establish are only true for objects/people that are "parallel" to each other, for lack of a better term. Say you have a row of houses and most of them are next to each other, those would all use the same vanishing points. But if you have 1 house that is rotated not-parallel with the others, it would have its own set of vanishing points. this applies for anything in a scene too- if you have a book on a table that's not parallel to the edges of the table, for example, it would have its own set of vanishing points as well, and so on. I can only do a crude mouse sketch to show this for now, but hopefully it conveys the concept This also helps add realism to scenes because if you try and force items to the wrong vanishing points, they always look odd.