I would focus on building confidence with your strokes. Everything is in the right place so I would concentrate on making the same strokes but pressing slightly harder and working faster. It may be hard at first but will lead to cleaner lines when confidence builds.
Hi Bart, your link wasn't working correctly so I fixed it up for you.
I agree with eoincassidy that more confident strokes (trying to capture things with a single stroke instead of repeatedly sketching in the same place) will help the fluidity of your gestures a lot! I'd concentrate on that and take it from there.
@Line: Image upload on the site is only available to members with a subscription. Some people also don't like posting things to multiple places and prefer keeping things tidy in one place. :)