Rewinds
Each time a rewind is used, you will lose one second of starting time. If used too often, you will lose too much time to make it worthwhile. Even if your car gets hit and it is now moving slowly, it still may be faster to complete this mission in this state instead of restarting.
Routes
Learn what to expect and how to drive. Each time you start a new area, drive as well while remembering the route to get to your destination as fast as possible. When reaching the final driver, intentionally lose the game and restart from the last checkpoint. Be ready to lose as little time as possible. The more time you save, the better the upcoming stages will be.
Turbo Boost
Do not use the Turbo Boost at all times. Consider the destination and how many turns that must be made and their difficulty. You can then decide if you should need extra controls or leave the car as is. Some slow cars get very slow by using the transmission. Be careful when selecting your boost, if any. Some missions can be completed easily without using a boost.