another thing i noticed in a lot of senior developers is that they don't stop at just one patch in the area. they send patches from one area in dozens, each building over the previous, or maybe not.
this might be because they notice problems as they go over the code and then as a consequence end up writing a lot of patches to fix those. but anyway, it doesn't hurt to look around the code that you just edited to see the bigger picture and fix the holes that you could find.
this in other words means -- be interested in how things work and not just complete the task you are assigned and say "i am done".