Encourage praise & criticism

Devise an organized system for suggestions and complaints
This can be even a box in which people put pieces of paper with suggestions and complaints written on them.

Establish “fix-it” weeks
Instead of working on something new, try to improve existing products, user experience, etc. during “fix-it” weeks.

Say “that’s wrong” not “you’re wrong”
This way, the employees will know that the criticism is not personal.

Praise your employees publicly, criticize them privately
They will be more appreciative and comfortable.

Create a safe environment for employees to criticize you openly
Show your employees that embracing criticism can make you do your job better.