Advices to sellers,to request and for buyers,to provide postal address,convenient for item delivery.
1). The proper name of recipient  (especially important for registered,insured or recorded delivery mail, where recipient obtains mail against signature):
The best thing is that the address contains full name and surname of the recipient person.
For example: John Smith, James R. Thompson
Name alike J.Smith on mail, may cause questions,whom is addressed the mail? To John Smith or to his wife Jessica Smith or to their son
James Smith, following this possibly giving item into potentially wrong hands, in rare cases may cause the conflict with recipient.
Addressee name alike John and Jessica Smith, may cause the request from postal authority for both people to come for the mail (the real practical precedent I had!)
Company name as the recipient name, say "A&B Projects Co. Ltd" will course the impersonal reception of mail, so it is better to mention along: Attn: Mr. John Smith or even better to request his homeaddress for mail delivery.
2)Street name and number aspects:
177 Seventh Road NE Apt.7 is better written than 177 7th Rd. NE #7, but 177 7 NE #7 short writing is an absolutely bad and could be misunderstood easily...
Remember also that courier postal services would normally not deliver items to P.O.Box addresses!
3)Postal ZIP codes are very needed for delivery (most countries do use their own, I thing only Ireland has none.)
Remember to write town/place and ZIP code: alike: Jersey City NJ 07302, or Worcester, Worcestershire WR2 4UJ...
4) Country of delivery should be written best of all in english or french (official postal language!), if it is "exotic" country, You may mention the continent in brackets like Latvia (Europe), but still some "clever" people at the postoffice may mix-up
Austria and Ausralia, Mauritius and Mauritania, Slovakia and Slovenia, Latvia and Lithuania...