You can get a lot of different highlights in long dark hair, including blonde or ash brown. The darker the base color, the darker the highlights need to be. The best way to achieve this look is by cutting the ends off of that and adding light-brown streaks to the tips. However, you should note that adding lighter streaks will make that appear thinner and less attractive. Instead of getting blonde or ash brown highlights, you can go with muted shades.
A long bob is the perfect choice for highlighting a deep shade of hair, but it doesn’t have to be blonde. Ashy tones keep the look multidimensional without taking away from the base color. If you want to add highlights to your long bob, you can start the fine-tuned highlights wherever the sun would naturally hit your locks. You can also go with a more subtle color, like chocolate brown.