One way you can improve the chances of people seeing you before they hit you is by adding some strips of SOLAS tape (Safety Of Life At Sea, used by the Coast Guard) to your helmet, gear, and/or bike. SOLAS is by far the most reflective of tapes.
These pictures show the 3M brand (don't cheap out on this) that is sold by Aerostich. In the first picture you can see that helmets just aren't that visible in low light.
On the helmets below, the second from the left has SOLAS tape; notice it reflects light well.
When it becomes actual nighttime, you are much more likely to be seen with the SOLAS in place.
The Hurt Report states that accident involvement is significantly reduced by the wearing of high visibility yellow, orange, or bright red jackets. One way to achieve this look is by wearing a bright, reflective vest. They're not the most stylish things, but one member summed it up well: "I'd rather have a cager say "Hey, look at that goober motorcyclist with the bright yellow/orange vest" than "Gosh officer, I never saw her/him." If you're concerned about airflow through the vest, look for a mesh one.
Motorcyclists who enter military bases are required to wear reflective vests. Icon has developed a functional vest that meets specifications for our citizens in service. They're not a bad idea for the rest of us, either. Your choice of two eye-catching colors.
If you look where they sell clothing for construction or highway maintenance workers, you should be able to find something like this. It's basically a surveyor's vest and is very breathable and lightweight. Harbor Freight sells a similar item for really cheap.
Bill H, with 50 years of motorcycling experience, recommends the Conspicuity brand. Conspicuity makes a variety of models and colors.