Some design suggestions:
- Maybe lose the hair. The whole species doesn't have to be bald, but a different style would stand out, a sideshave perhaps if you want some hairstyle.
- Ear shape, perhaps round them off and reverse their direction
- Alter the shape of the head. It doesn't have to be radically different, just different enough to make you realise that this is someone who isn't human.
- Exaggerate other body parts. Even with a long neck, she still looks quite humanish. For example (so I don't mean you automatically do this), look at the Skrulls in the Marvel universe, besides their green skin, what really sets them apart and stand out as aliens is their chin.