Require your students to do boring and repetitive pronunciation in class or homework much? (Do you hold them accountable for quality practice outside of class?) If you have been following the blog for a while, you know that I am a big fan of James Clear. If you need to change something--most anything--and you probably still don't need a coach or therapist to help get you there, his website is worth a visit. His latest post, "The Behavior-change paradox", combined with Eduardo Briceno's TED talk on "How to get better at things you care about" forms a nice program for change of sorts--even pronunciation change!
"Deliberate practice" is back in vogue. One of the great "myths" of our time is that most anything can be learned at near light speed, relatively speaking. The typical pitch from quick-change methodologists (and con artists) such as "change your accent FAST!" reflects that legacy of both behaviorism and technology, especially the latter--and marketing, of course.
The two pieces of the Clear-Briceno model are (simply) consistent, incremental change and focused passion. You need both. Clear's analysis of why we often fail to make change in our habits is simple, but striking, and captures the passion-practice paradox: the more we try to change in the short term or the harder we go at it, the more resistance we encounter. Effective change over time is generally based on disciplined alteration of key practices at the day or even hour-by-hour level.
Do you do that? How is your "passion-practice" balance, especially in assigning homework or getting learners charged up, self-directed and autonomous? If you function in a language lab or do a lot of pronunciation on the web, you may be off the hook somewhat, of course. Now we know why the lab and technology are making a serious comeback in the field--and may eventually replace us all!
In the meantime, if you are having issues with your diet, exercise, budgeting or metaphysical discipline, check out the Clear post (and maybe even download is longer, more detailed instructions on how to get your act together.) Then have a focused, professional talk with your students on incremental, manageable practicing of their pronunciation and their L2 in general . . . regularly.
Before you do, you might also want to check with your local personal fitness training coach or "haptician" on some effective ways to do that!