Enhancing
Enhance your cards to their maximum level. Farm a level that gives at least 2-star cards as a reward until you have a large amount of them. Then, use them to enhance your main cards. Do not spend all your cards by doing this, as a large deck will be required. After you fill all your spaces, always use the weakest cards go to enhance the strongest ones.
Restore energy
Instead of waiting for your energy to be restored, advance the time on your device. Afterwards, set the time back it its correct value.
Various Tips and Tricks
Do go out of your way in order to pick up any materials that you find lying in the road, as these can be used to craft new arrows which boost your score in the archery sections, or improve your skills to help you perform better on every run.
Free coins!? hit the icon at the top-right hand corner of the main screen. From here, you can watch a few videos in exchange for 100 coins each time.
Improve your attributes first since these affect your performance and currency-gathering on every single run, not just when you encounter archery sections.
When you go online and start racing against other players make sure you've crafted your arrows. Having a solid selection of these will allow you to get a much bigger score during the shooting sections - and all things being equal, this can make the difference between the winners and the losers.
Cards...