How can we minimize traffic loss after a domain name change?

[Jacob]

As you have written, the old domain has been working since many years so you wouldn't loose this. But you are going to launch new one.
My suggestion is to do 301 redirect of your old domain to new domain. The new domain will get all the credits of your old domain if you do 301 redirect of your old domain to new domain. For traffic, you should start social median campaign for new domain.