If your main concern is not beeing seen, there are a few things you can do. In most sports clothing shops you'll find "night running" product lines which reflect light.
A cheaper alternative are these safety vests that e.g. road workers wear.
Add to that some bracelets with blinking LEDs, and people should be able to see you quite well.

If you are more worried about safety, I guess it depends on what kind of area you live in. Maybe you can find a street where there's still trafic after dark, so you won't be alone. Take your phone with you, and maybe pepperspay or one of these high-noise-alarm-thingys, if it will make you feel safer.

I run in the morning in the dark and wear a LED arm band that flashes red. When it's dark brighter colors don't make that big of a difference you need some reflective that will shine in headlights.

As far as safety, I don't worry about that since it's very safe where I live. However, I agree with nikkiwolf, get yourself some pepper spray to carry. Many have clips that make them easy to attach to your running gear.

I have ankle bracelets that velcro on that are LED blinking lights. I tried to wear them on my arms but they bothered me. I bought mine at a race expo.

headlamp and run against traffic so you can see the car coming at you. If you think something bad is going to happen pull your phone out and pretend to call someone, that should scare most weirdos away. Also depends on where you will be running, bad area or crazy wildlife area probably not a good idea without a partner.

I wear a neon yellow jacket from nike and it does the job well. I am concerned about my safety so i tend to avoid running at night though.

I do most of my running in the dark due to my work schedule and the sun not correlating to my liking and it's kind of nice actually.. I carry a small light that I originally purchased for biking but it wasn't bright enough to use on my bike (I need to see quite a bit ahead of me for biking, not so much for running). This light serves 2 purposes - Cars/other pedestrians can see me coming (always running against traffic and the movement of my arms keeps the light going all crazy so it's noticeable) AND I can shine that sucker down by my feet if I don't have enough light to see uneven pavement or whatever might be there.. It also comes in handy when someone is out walking with or without their dog and are not carrying a light because I can see them before I'm on top of them and move over so their dog doesn't freak out I also have a red blinky strap I put on my right arm. I refuse to run at night without my phone. Bright colors help during the day and are better than black at night but.. meh - reflective stripes are better as everyone else has said previously. Those blinky lights and LED flashers are pretty cheap, pick one up!

Safety is a whole other ball game and if that's your concern.. Running at night can be sooo nice but it can get a little sketchy. Just keep on the busier streets and stay alert or if you feel safer on a quiet street that you're familiar with that's okay too (I have a couple of these and they are lined with houses so if anything happened I would most certainly head to the nearest one and pound away at the door). If someone looks a little.. scary you can head to the other side of the street or whip out your phone and scream "I know karate!" haha. Good luck!

I run the same route around the same time every other day or so.. In doing so I know who is a "regular" out for their daily walk with the dog or alone and who looks like they don't belong. I guess it depends where you live though. I am running in a residential area that is fairly quiet but not dead by any means.