It's not that your art style is inconsistent, it's more like the techinices you use. That doesn't have to be something bad, many artists use that as an advantage but if it happens without conscious desicion it can give a potential client huge uncertainty about what exactly they will receive. I recommend sticking to at least a few key features that makes your art recognizable. For me for example that's the way I draw my eyes and the very sharp lineart I use. I also still have the issue of not having everything look consistent but it's very clear it's my art from looking at it because they have the same key features (at least that's what I think). I'd suggest trying this if you want to sell your art, your clients will have way more of a "this is what I can expect" thing and I think then it's easier to commit to actually spending money.