KO vs. AKO:
1. "ko" is preferred to emphasize possession of something:
"bag ko ito" (this is MY bag)
"ako ang may ari ng bag na ito" / "ang may ari ng bag na ito ay ako" (I'M the owner of this bag / the owner of this bag is me).
although the 2nd example is correct, seldom you will hear any filipino go by this phrase in daily conversation.
2. Form of (Tagalog) verbs - the infix "um" and "in" - "um" is used along with indefinite article as opposed to "in" which comes with definite article:
let's say the verb "take" / "get" (Tagalog - "KUHA")
kukuha (future) + AKO
kUMuha (past) + AKO
kUMukuha (present) + AKO
kukuhaIN (future) + KO
kINuha (past) + KO
kINukuha (present) + KO
"kUMuha AKO ng isang baso na tubig" (I took A glass of water)
"kINuha KO ang isang baso ng tubig" (I took THE glass of water).
KA vs IKAW:
one among their basic difference is the way they are positioned in the sentence. "IKAW" is most of the time positioned at the start of the sentence while "KA" in the middle.
"IKAW ay pumunta sa barrio." (you go to the barrio)
"pumunta KA sa barrio." [(you) go to the barrio]
again, I would say that the 2nd sentence is the conventional way of saying it.
Hope this helps...