You can get a boost easier by doing drifts. However press B, drift, then keep tapping B for a better chance of not crashing. Also, drive on the wrong side of the road to receive a boost faster. If your opponent is in the wrong lane, follow him, but not to closely. This allows him to pass the traffic for you. Also, if he hits someone you can get out of he way if you are not too close. This is unlikely however, as the CPU follows the cars through a safer route. As long as you do not disturb him he will not hit anything. This will give you a faster and safer boost. Additionally, when you get a full boost meter, you can gain and use boost a lot faster by tapping A (Boost) button instead of holding it down and draining your boost all the way.