If you don't already have observations built into your teaching schedule, make an effort to engage in them.
I believe all teachers should observe and be observed regularly. And not just by superiors for appraisal purposes.
Observations (both by and of) are an incredibly valuable source of development. If your school doesn't already facilitate them as a standard, try the following:
Ask your superiors if they can incorporate peer-observations into schedule.
Invite your peers to sit in your classroom and share their feedback after the lesson.
As your peers if you can sit in on their lessons to pick up some techniques and approaches from their teaching.
Offer feedback after observing, but if the teacher doesn't want feedback, then perhaps keep it to yourself (though it's really up to you how confrontational/disagreeable you want to be!).
Answer in the comments below (I really want to hear from you!):
If observations make you nervous, tell us why.
If you have observed or been observed recently, tell us something you have learned.
Pro-Tip: This doesn't only have to apply to teachers. Whatever you do, try asking a colleague to observe your performance and give you some feedback. Offer the same in return.