For anyone that's had 'that feeling' where the Art just doesn't seem to come to them, anymore, or has taken a hiatus of sorts.
Here are some things you could certainly try:
Step 1: Clear the cobwebs.
Most artists, at some point in their lives, will eventually feel disappointed with their own style.
Something will just feel off or wrong; one may even be tempted to toss out some drawings at this phase. One can do this, as the artist's work and choices are entirely up to them; but it may do good to keep at least a few pieces for future reference. It'll give you a chance to see how you've progressed and how far you've came, as in those "2000 vs 2012" drawing exercises.
Like most phases, however, it'll come to pass.
What you may want to consider is furthering the skill you have into another medium/style/method by progressing.
Take some chances.
Treat mistakes like a new opportunity.
Take more time on individual pieces than sketches; or vice versa.
Draw and create...
without bounds.Step 2: Don't get caught up in inspiration.
This is as tempting as tossing out your work.
Viewing any art that leaves a lasting impression and wanting to at least respect that vein of style or substance is inevitable. It is not solely juvenile; some artists do quite well using references and either redrawing them with different features/styles or utilizing a photo/image in a collage. This is only a natural part of creation; it is not so much plagiarism as it is taking something and making it yours in its own special way. The ever-present laws of copyright and licensing make this difficult for all aspects, especially music and artists like Daft Punk, Girl Talk, Justice, DJ Shadow and the like that 'sample'. This has been present in art since its beginning.
However, it is a good exercise for the creative brain to bring something wholly from within yourself; be it a spark of inspiration, the way someone said something, or the feeling evoked from a certain song/film. It trains your brain to create when there is nothing to rely on but one's own imagination, and that can never be a bad thing. It just takes a little bit of trying and practice.
Step 3: Don't stop drawing!
This
cannot be stressed enough.If you feel you can't go on, perhaps you need a shift or change of pace.
Clear any clutter in other aspects of your life. Remove mental blocks, self-imposed or external. Create a space you can create in. Try new things creatively, and new things will come out of you, create-ed, as a result.
If you tire of drawing, write something, even if it's just a simple fragment or sentence.
Take the creative energy in you and bring it forth, and you will soon find that there is more going on for you than you could have ever even hoped for.
All this will (hopefully!) help you on your creative path.
The road ahead need not be tough; for with the right tools and state of mind, m-anything is possible.
Good, Luck.