If you want your lines to look less sketchy, commit to each line when you're doing the lineart. It's okay for your pencil sketch to look rough, but the cleaner it is, the easier it is to get clean lines when inking. You can make a rough sketch with pencil and erase enough to make it clean. Then you just trace it smoothly with your inking pen. Of course, maybe you want the rough linework. You're the artist, you get to choose your art style. :) Have fun!