If you are getting frustrated with a task you are practicing, leave it and come back. In the interim, your brain will be digesting and organising the information you have given it. When you come back, you may be surprised at your improvement. Not only are you refreshed, but your brain has been working subconsciously on the information while you were doing another task. That task can be another related task or something completely different. So, it is actually better to "interleave" your learning and not take any exercise to full completion. Move back and forth between activities and harness the power of interleaving. And no, this is not multi-tasking. Stay away from that. It has been proven to minimise your effectiveness is all activities.
Dr. Michael Kearns
Musician, educator, husband, father, web designer ... my life is like a mosaic with each piece vying for my attention.