Well, short 'how to' about BF1 / Aston National.
Try to exit the last chicane as fast as you can. You want to hit the finishline as fast as possible.
T1 is hard to get perfect, but because of the massive downforce on the BF1, you won't lose much time if you got a little wide or a little too much to the inside. Perfect would be, braking a bit (just tapping the brake), and shift to 5th while you do this. Don't get fully off the throttle. Slowly apply more throttle before you hit the apex. By the time you're at the apex you want to be pretty much on full throttle again. Then let it roll around the outside, for more momentum.
T2, brake a bit before the curbs start, about between the bridge and the curbs. Drive about half on the curbs, appearantly the curbs don't really have less grip. Press full brakes, and get off the brakes smoothly as you get to go slower. Use 2nd gear, don't shift to 2nd to early, but just before the apex. You want to go on the throttle around the apex, gradually apply throttle. Try not the hit the inside curbs, the outside curbs are ok.
T3 is pretty much the same, but try to turn in a little later compared to T1. The apex is not halfway the turn, but a bit afterhalfway. Use 2nd gear again. At the apex you have to get on the throttle again. Don't go too far to the outside, the big bump makes the TC work, and you lose time.
T4, brake at the 100m mark. Brake on the curbs again. Use the camber of the turn to slow down a bit more towards the apex. About on the apex you apply throttle. Don't use the inside curbs and don't go too wide on the exit, because those outside curbs are a bit less cambered. This turn can be done in 2nd or 3rd, depending on the gear settings. For me 2nd is a little faster, but harder to control.
Final chicane, brake before the red/white/blue curbs start, 2 wheels just over the line. Start to turn in a little after the red/white/blue curbs start. Shift to 4th gear. Try to go as much to the inside as possible in the first apex, this will probably result in 2 wheels on the grass, 2 on the curbs. However, if you go too far to the inside, you will lose too much grip and speed. Apply throttle as you approach the first apex. By the time you're passed the apex you have to be on full throttle again, in order to get out of the turn fast. Wait before you aim for the 2nd apex, you don't want to get too much to the inside. Only aim for it when you are with 4 wheels on the ground again. Before you know it you will be passed this apex. Use all the curbs on the last apex and the outside of the turn.
The last turn requires a lot of practise to get fast. This is also were a lot of people crash because they go too wide in the last apex of it. To prevent this, don't enter too fast, drive as straight through it as possible and don't get too much to the inside of the 2nd apex. This will let the car jump too much to the outside.
But to master the BF1, it's smart to start with the FBM/FOX. Then get the FO8 right, since this on is very hard to be fast in. When you get fast in that, try the BF1. Just because it has traction control, doesn't mean you can use digital brake and throttle. I totally agree with george_tsiros here.