How can I improve my driving in these areas?

I'm a new driver, and I've got my license, but I still don't feel confident in my driving. I seem to drive too close to the ';parking lane'; I guess it's because I fear that I will graze the car on the opposite lane, but I might actually graze a parked car, though. Lots of roads in NYC are narrow. I also do not have much experience in changing lanes. It seems experienced drivers just glance at their rear and sideview mirrors and are able to change lanes easily. I'm having trouble judging the sideview mirror, what should I be looking for in the sideview mirror? What would indicate that the car is too close to my bumper and that I shouldn't change lanes? I also have trouble finding parking. Driving at 30mph and scanning the road for parking spots seems to be very difficult for me. The driveways keep looking like parking spots to me.How can I improve my driving in these areas?
Use the center of you hood to gage your distance from the parking lane. Picture an imaginary line running down the center of your hood and line it up (visually) with the painted line on the shoulder of the road. If there's no painted line, pretend there is, it'll still work.

As for changing lanes....you look in your rear-view to make sure no one is coming up fast behind you, check the side mirror to make sure no one is beside you and ALWAYS do a shoulder check to make sure no one is in your blind spot.How can I improve my driving in these areas?
Confidence in your driving will come with time and practice.