I’m not sure what hair color you are at right now, I’m guessing either red or your natural brunette. I’m also a little fuzzy on your hair length so I’m going to just throw out a few suggestions, if you want something more specific send in a pic.
If your hair is red right now I would bring it back to your natural brunette and cut it pretty short to give your hair a rest. Because of the shape of your face a bob or a cut similar would suit your hair. Also the shorter your hair the less damaging the chemicals are to it. It’s going to be pretty hard to go from the red to the blue with out bleaching all of your hair which can be pretty damaging if you’ve bleached it recently to get to the red. However, a black bob with blue highlights would look fantastic! I love blue and black together. Summing up: if you have red hair bring it back to your brunette and let it grow out to avoid damaging your hair more.
Now If your hair is your natural brunette you can go in and directly do some blue or do the black and blue, which ever you prefer. You can even do a deep brown with some blue highlights, tip dye, bang accent. If you don’t want to go completely black.
While searching through pictures I found this! If you hair is red you can probably get to this and have the color work well :)
short black and blue hair:
Blue and brown hair:
bob (replace the purple with blue)
Ok just let me know if you want more specifics. Those are just some ideas/things to think about.
Hope this helped (a bit),