It really depends on what your goals are. I'm trying to lose weight quickly so I put a lot of stress on my body when I run. The key for me is to focus on my form, and more importantly to get into a very strict breathing rhythm. When I run I'm literally focusing on only those 2 things, which is strangely enough a big part of why I enjoy it so much. No thinking about work or life or whatever, just clearing my mind and counting breaths. I rarely listen to music too because it can be distracting when I'm trying to focus on breathing patterns. You can try out different patterns to see what works for you, but it's definitely something I recommend for anyone who is looking to run faster and longer distances.
Just as an example, when I start my run I'll breath in for 4 steps and out for 4 steps. I literally count 1,2,3,4 and then out 1,2,3,4. Over and over and over. Once I start getting tired I'll go in 3, out 3 or in 3, out 4. Sometimes I switch it up but just finding a pattern that gets you into the zone really helps distract you from the "pain" of running. Also, you can push your body way harder than you think you can do don't be a wimp about it! That's what I tell myself when I"m at mile 3 or 4 because it can be tempting to call it a day early.