what possibly can i do to make it look better

I would say a good tint on the windows, lower the car and some nice wheels and tires that don't look ridiculously too big. We use to have a friend with one was a dark blue I30 and a lighter blue HID bulbs really made the car look good. I am a purest and don't like junking up cars to make "them look good."

I would check out NICO's Infiniti section to see what other people have done with theirs.

I have the same exact car and I tinted the windows last week, 30%-front and 5%-back and it already looks a lot better. So to start off, do that first. I'm also thinking of putting a custom sub in it because the original one doesn't work anymore. Later on, I might install a pair of 18s or 19s, I'm not sure which ones yet.
So do something to that effect. I don't know really know how you would like your car to look but these are some ideas that I might use in upgrading my car.
P.S. If I do install the 18 or 19 in. rims, I might lower it just a bit, but that depends on how it would look with the wheels.

Get some new rims and go on ebay and get some new headlights and taillights.