mejor amigo (or amiga if the best friend is a girl)
'No soy tu mejor amigo?'
Best of luck to you my friend is very easy to translate. Best of luck to you my friend = mejor de las suertes a mi amigo
google translate my friend, google translate
go to google translate or ask a spanish speaking friend
Voy a traducir esto a mí mismo is the best way to say "I will translate this myself" in Spanish.
If a person is a 'family friend', then that person is also a 'friend of the family'. Accordingly, the Spanish phrase will be '(that person) es un amigo de la familia'.
Eres la/el mejor.
In spanish, "best friend" is mejor amigo(a), amigo is for a boy and amiga is for a girl.
My best friend.
Por mi amigo mejor. - By my best friend.
lo mejor de la suerte
There are many ways to translate that, but I think that the best option is "barato"