Axis based on 2 Vectors

I'm a little hazy when it comes to vectors, maybe some of you can shed some light on me. I'm trying to generate an axis based on 2 3D vectors. What I mean is, I want +Z to go down the vector +X to go to the right of it, etc. This is what I have so far:

Code:

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Vec3 Start, End, Final;

Final = End - Start / |End - Start|; // Gives me the vector from Start->End

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And that about sums it up lol. I was thinking maybe a couple cross products could give me the data to work with, but I really don't know. If I can't get an axis to work with, what would I need to do to get a point to the right of the vector? Maybe this?

Code:

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Final.x += 2.0f; //?

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Anyone have a clue to what I'm talking about?

Figured it out...