It's possible to skip 2 races in GP2. simpleton216 discovered that if you retire from a race, the positions of the AI when you retire are used to determine the standings. Right below are 4 different possible standings for Airport and Palm Bay, as well as how to achieve them. The table at the bottom tells you what strategies to use based on the points of the AI after the 2nd race (Interstate Loop).

To block a car effectively, tap brake and hold accelerate (as if you were doing a boost start). However, do not let go of accelerate throughout the countdown, as you don't actually want to boost start. Turn during the countdown, without holding boost, towards the car you want to block. When the race starts, move in front of the car, and you should block it.

Airport Terminal 1 & 2:

1. 2nd (white), 3rd (red), YOU, 1st (black) (immediate retire)
2. 3rd (white), 2nd (red), YOU, 1st (black) (couple of frames)
3. 2nd (white), 1st (red), YOU, 3rd (black) (block black car on right)
4. 3rd (white), 1st (red), YOU, 2nd (black) (aim for side of black car on right, brake on contact)

Palm Bay Marina:

1. 1st (black), 2nd (white), YOU, 3rd (red) (immediate retire)
2. 1st (black), 3rd (white), YOU, 2nd (red) (block white car on left)
3. 3rd (black), 1st (white), YOU, 2nd (red) (block black car on far left)
4. 2nd (black), 1st (white), YOU, 3rd (red) (block black car on far left a little, let it pass to confirm)

Scoreboard (Airport/Palm): 4b,2w,0r 4b,2r,0w 4b,1w,1r - 3/3

4w,2b,0r 4w,2r,0b - 2/2 4w,1b,1r - 4/2

4r,2w,0b - 1/1 4r,2b,0w 4r,1w,1b - 1/4

3b,3w,0r 3b,2w,1r - 4/3 3b,2r,1w - 3/4

3w,3r,0b - 2/1 3w,2b,1r - 3/2 3w,2r,1b - 4/1

3r,3b,0w 3r,2w,1b - 2/4 3r,2b,1w - 1/3

2b,2w,2r - 3/1