"Even though" is used when the condition is actual.
"Even if" can be used if the condition is hypothetical, or in the future.
Even though we go there after midnight, my dad was waiting up to greet us. Even though they already have four kids, Mary wants to have another baby.
Even if we get there after midnight, I bet my dad will be up waiting for us. Even if Mary had four kids already, after she held that baby at the party, I bet she'd still want another.
However, you will hear "even if" used for actual conditions too. She's my best friend, even if she is a little silly sometimes.