what tablet are you using?
I mean honestly, it just comes down to practice. I've been using a digital drawing tablet since I was 17....so that's almost 10 years practice. And when started I had to get really tight sketches and get REALLY REALLY REALLY zoomed in for details and I also rotated the screen (Rotate View Tool (R) in photoshop). So, for example if you were drawing a arm but it's at a weird angle, I would rotate screen so I could draw it straight down, bc it's easier to pull the pen straight down then it is to draw at an angle.
Also the faster you work, less lines you produce and longer strokes you use, the smoother it should look. Also practice you're line weights and look at other comic work and see how they weight their lines. A lot of times you can use a larger brush with the pen pressure and do small strokes to add up to a smoother look.
Also photoshop didn't really work for me when I was starting out because i just didn't understand the program and that's when I went to SAI. That helped me be able to jump back on Photoshop for some reason. SAI feels more natural. You can also download more brush looking PSD brushes, sometimes that helps. Depends what you're trying to accomplish.
Now being professional and out of college I jumped onto a Tablet Monitor and drawing directly on the screen does make it so much easier but I'd conquer what you're doing now before spending 1000s. It's not so much the program or tools you using as it is how you're using the tools.
And one last tip, layers are your friends! When I draw my comic I have a rough outline sketch, rough sketch, lose sketch, tight sketch and THEN I ink. I usually end up with about 5-7 layers before I even ink anything in the computer but I'm drawing directly in the computer now.