Hello There!
I am also natural and I trim my hair myself (for the most part) There are times when my beautician may do them if I slack up on my self trim. But when I am consistent, there is usually no need for her to go-over my work.
Anyway, this is what I do...
I oil the last 6 inches of my hair with vaseline making sure I cover the ends.
Then I put my hair in about 8-10 two strand twist and wisp across my ends with good trimming scissors.
SIDENOTE: After oiling my ends, I can usually tell how much needs to be trimmed. How you ask? Well, if after oiling my ends with the vaseline and they still feel "course" or look unruly, then I know that the unruly course end-parts need to go.
hth,
-lee
I usually my my hair in about 8-10 two-strand twist and then trim the very ends of each twist.