Right now I'm still shooting everything that appeals to me because of lighting, moods expressed by a scene, and graphic details. Some of my shots are taken while doing long bike rides, some on my way to work in the AM, & other from weekend morning photoshoot jaunts! I feel as though my subject areas are too varied - but I guess that's more typical than not. I'm shooting with a Nikon D300 and older D70S. Usually with 70-2002.8 Sigma and a 300 F4 Nikon.
So, to get better, one just has to "get out and keep shooting"! I'm sure the critiques from this site will be very helpful. I've seen some absolutely beautiful photos on this site, representing great talent.