Go to a salon and have a professional stylist help you. If you just get highlights, it is less expensive and doesn't take as long, compared to highlights and an all over color, which would be more expensive. There are kits to do highlights at home, but you may not be successful.
If your hair has not been previously colored you can highlight your hair with regular hair color a few tones lighter than your natural color. If you want a lighter color or you have dye in your hair, you need to used a highlight product with bleach. Small strands of hair will separated and the bleaching product will be applied.
I would recommend going to a hairdresser because sometimes the chemicals in the boxes can react badly with your hair color. If you use a box, make sure to wear the gloves and choose a color that will complement brown.