As a DP, I am always asked about ways to make to make a film look good with minimal resources. People are always wondering about this camera or that camera, the benefits of one format versus another, or creative ways to light without a lot of expensive gear. All of those things are important discussions to have of course, but nothing will affect your image more that what's actually in front of the camera. Locations are far too often neglected on a low-budget film and they will ultimately have the greatest impact on how that film looks in the end. In fact, I think the DP often gets credit for making a film look good, when the location itself is actually doing most of the work.
You can shoot on 35mm, and have all the crew and gear in the world, but the fact is, a room with four white walls is just never going to look that interesting. On the other hand, if you're shooting someplace that's already beautiful, you could shoot it on a cell phone and it will still look beautiful. Take this iconic image from Lawrence of Arabia, a film that is probably as known for its outstanding cinematography as any film in history:
Somehow it just doesn't quite have the same impact. I don't mean to belittle the excellent work of the legendary cinematographer Freddie Young, but I definitely think having some nice scenery to work with probably made his job a little easier.
I understand that there are other practical considerations in play, and the uncle's house that you can get for free may be the only location you can realistically shoot in, but sometimes it may actually be worth it to pay for a location or two. After all, you're paying a DP and a film crew, renting equipment and paying for all kinds of expensive stuff to make your film look good. Don't skimp where it's really going to count and try to make your basement look like a working operating room. It can be hard to find great locations for free or cheap in New York or LA, but you might be surprised at what you could find for little to nothing if you're a couple hours out of town.