Lots of good advice here, I went from dirt to street and still ride both using my VFR 750 as a daily driver untill its really cold or icey.
Going from dirt to street the hardes thing for me was understanding the power of the front brake. On the street you need to YANK the front brake to the handel bar, no, the bike wont flip and the front tire will not lock up and skid as it dose in the dirt, the rear will get light under heavy breaking so try to only use the rear brake for slow speed breaking and use down shifting with the front brake for most braking. In a panic brake, its a handfull of front brake only, hitting the rear brake will cause the rear tire to lock as the weight transfers forward and when a rear tire locks, it will try to come around and see what all the fuss is about, not good.
Other than that is making your self visable but putting your bike in the sopt wich often means a mix of lane position and following distance. When you see cars that might pull out into the road in front of you, make eye contact with them to make sure they see you. Ive been down like 4 times and only got hurt once on my first street bike becuase I drove it like an idiot. Yeah people still pull out on me and cut me off, most of them see me and still do it, but knowing how to handel the bike and use the brakes and my dirt bike experiance makes short work of most of it. On the interstates as was said, you have to "walk" other cars by your spot. I like extra following distance in the interstates but around here, if you leave a car lenght, in front of you, they will put a car there, so as a car comes by, I accelerate with them just infront of the door and "walk" the car to the back of the car infront of me to say, This is my space, dont pull in on it, and they as they go by I resotre my following distance. Extra following distance is important, not because you need it, a motor cycle can easaly out stop a car by almost half the distance, but becuse the people behind you need it to stop and not run YOU over. If you ride street for a while you will start to get those alarms in your head that warn you of a potentially dangerous situation and how to avoid or minimize the threats. I find riding slighty aggressivly especially on interstates is also the best deffense, it keeps you moving through the traffic and in everyones attention.
Where your gear, riding jacket, long pants, good boots and GREAT gloves, a good helmet, not the best, but a good full face. Riding dirt bikes has also helped me stay up a few times many riders may have gone down, it helps me not fixate on obsticales but look and ride through them instead.
Get used to your bike and then take it out and have fun, I LOVE riding my street bike almost as much as I love dirt riding and I hope to never give it up.
Words of advice barrowed from pilots:
There are Old riders and there are Bold riders, there are no Old Bold riders.
Is your bike a 2 stroke tripple? those are cool, I have a 1972 Yamaha 250 2 cyl 2 stroke I am getting ready for my girl friend to ride on the street, those things are a blast! Noting like blowing a little smoke on rode and seeing peoples heads turn from the ding ding ding ding, Baaaawhaaaaaaaaaap!