>>3687078One of three things is happening:
1. You're just tracing instead of inventing the line. Like all traced art, this results in a stilted, lifeless piece because you're effectively shutting off the artistic part of your brain and just performing mindless pattern matching. Remember, you aren't drawing in pencil - you're drawing in ink with a pencil guide. Use a looser, less detailed sketch and reduce the opacity of the sketch layer so that you aren't as focused on copying the sketch and can instead focus on drawing with ink. A lot of times you can even get away with not overlaying the inks at all and just keeping the sketch off to the side as a reference. Do some straight-to-ink drawings with a real (non-digital) pen or brush as well to build confidence and decisiveness with permanent media.
2. Your pencils are too dark and are obscuring your inks as you work. This one can really sneak up on you: you finish up the ink and it looks fine with the pencils still underneath, but as soon as you remove the sketch you realize the inks can't stand on their own. This is a big reason why many artists use a light blue or similar color to sketch in rather than grey, because it's easier to visually distinguish from the ink. Never sketch with black, and try capping the maximum opacity of your sketching brush to 75% or so. In addition, bind the visibility of your sketch layer to a hotkey so that you can periodically toggle it check your work and make sure it looks right without pencils underneath.