I understand your feelings on this matter. As a female martial artist, I have learned that even though I am well-adept, I am still small, and many will inevitably view me as a target. I had a friend who jokingly called me a Poodle; even though a Poodle may bite just as nastily as a German Shepherd, most people don't take them seriously because they don't look threatening.
As a result, I needed to ensure that I eliminated any "misunderstandings" as much as possible. This did not mean going around and acting aggressively, as one poster also stated; rather, it meant eliminating any body language that would suggest that I am an easy target. For instance, don't look down as you are walking, and make sure that you are constantly aware of your surroundings. Not only does this mean looking around and turning your head, but paying attention to your peripheral vision and listening to voices and other noises around you.
Pay attention to vehicles on the street and anyone who looks sketchy. If it comes down to it, take a detour if the person in question is close to you or heading in your direction. You can easily talk to yourself and say, "Oops, wrong way" to imply that there is no fear (this also allows you to see if you are being followed). Noticing a sketchy person from a distance will help a lot. Pay attention to his/her body language and take caution when you see groups of people walking (especially at night). Walk with other people if you can because that easily cuts the risk in half.
If you are confronted, be firm, look the person in the eye and politely ask him/her/them to leave you alone (being louder can attract attention, which attackers hate). Show that you are not afraid and (regardless of whether or not you can get hurt) are not a victim. The way you walk and hold your body up says a lot. Most people gain their first impression of you based on your body language (which is especially helpful in interviews, heh). If you look like someone who won't be easy to take down, an attacker will be more hesitant to attack you.
Another option is to increase your martial arts skill set (it never hurts to learn more; we all do) and/or carry a weapon on you. Look at your country's restrictions and find an appropriate weapon to carry on hand. Whether it be pepper spray, a knife, a gun, a kubotan, etc., if you are walking by yourself (or even in a group), it can certainly work in your favour and give you more confidence (which will make you appear less like a victim). My boyfriend is a fencer and always carries a knife on him. Even though he doesn't know many empty-hand techniques, he certainly knows what he is doing (I am the black belt and I feel safer with him). I have also carried a kubotan or knife in my hand whenever I amwhen in a deserted area (usually on campus) and/or when I see people ahead.
Mostly, I try to avoid questionable places and questionable people. There was a saying at my old school: "The best self-defense is not to be there." I feel that I have avoided many potential situations. However, regretfully, there have been times where I was in areas that I probably shouldn't have been. When that happens, you need to go with your instincts and try to get out of the area and/or situation as quickly as possible. Ultimately, keep your wits about you and pay attention to your environment. That is your best friend.
I hope that helped.
Good luck.