"Me too "me neither" "me either" "also I"
Could someone explain how to say that I think or I do the same as another person? I make such a lot of mistakes about it, I need help.

Question

Answer

"Me too!" when you agree with their likes/actions.  "Me neither!" (or "Nor me!") when you agree with their dislikes.  Forget about your other options.

Answer

"I like popsicles." -Me too! (more direct response to a statement)
"I don't like rude people."-Me neither! (more direct response to a statement)
"I don't believe in slavery." "I don't think they should raise taxes." Nor I! (more of a detached agreement)

"Me either" is not used along with "also I". Use the first three examples and you should be good!