This will come naturally, so dont worry about it...some of the later events requires you to stay alive longer, for just silver.
For the endurance events, you should choose a fully upgraded military truck (gained from getting silver in the drivers event, which is the third race)
Its easier to control, as its not as fast, and huge, so you hit a lot more boxes and zombies for extra time.
Worry more about kiling and destroying stuff, while keeping a steady pace, than just speeding through.
For most events i got gold in first try, ranking top 50 on the World leaderboard using this strategy, without even trying