well not sure about others but i promote one of my .tel for my business as domains is just a part time hobby for me

or rather a future saving/investment and let me tell you i am quite successful at it not only buy them able to reach me but its my only point of contact for anything related to my company they want to know
the best practice for people to know about your .tel
1) i am sure many people use signatures in email
a) just add your .tel to it and always keep it updated so your customer never look
for another when you can always be around or your support can assist them.
b) also add a tag line to your .tel ( eg :
i) Reaching us is easier now
ii ) .tel us anywhere and we will help you
2) incase someone ever calls you to ask your email or phone number/ fax number or any
contact information try to tell them if they can access a web just yourcompany.tel and that's
how it spreads more as word of mouth
Shahid