Ahleong, nice attempts to shoot there.   Got some comments for you here...

The RQ with umbrella is hard to get the good exposure on her face, so if you manage to find someone to hold an reflector there, that would be great.

Then the panning shots (don't think you pan too much, eh) not look panning at all. The shutter speed too fast to freeze the cars in action. They are like parking at the tracks.

Just my 2cents here, mate. Nice attempts! Some shots are great! Particular like that shot from the crowd!

Use a lower shutter .e.g between 1/60 to 1/250 etc depending on where u pan (straight way or turning). Focus lock the area where u wan to take the pix. Then when the car coming, just follow the car via the viewfinder till the spot u have ur focus lock at and press ur shutter.

Me newbie too. haha