Experimenting with Double Exposure

So, yesterday, me, the other intern, and my boss were talking about double exposures. I knew my camera had the ability to double expose but I didn't really know how to work it. So, we tested it out a little bit in the office and then I went outside to experiment.

I also knew I was going to take portraits later that day so I decided to try it out.

ISO: 320

Aperture: 2

Shutter: 1/500

These are both of them, one in black and white and one in color. This was my first try doing a double exposure for a portrait. Obviously, there is a lot to be learned. I picked this one to talk about being it was kind of like a happy accident. This was probably the 4th double exposure I had taken of her and after a while I just gave up. 

I accidentally got her eye to match up with the line above the word and I think that's why I like it. This picture isn't exactly what I was going for, but I still like it for some reason.

What I don't like about it is that the second picture cuts off on the right and the rainbow stops. I also don't like how the word is covering her face.

I'm looking at this picture now and I know what I should have done. I should've taken the portrait of her first, and then change to a wider lens and make the "vacuum" look smaller and layer it to where it would read at the bottom right. That would mean all the rainbow color was still there and the word would just cover up her hand, etc. 

I really want to try with double exposures because I think they're cool. I just need to practice.