One free spin is allotted to you every day. Take advantage of it, along with daily challenge to earn gold.
Gems
Complete the achievements to earn gems. For achievements that require collisions into seagulls and palm trees, work on building those totals on races that you know you will not finish well. Gems are also awarded for completing levels that also unlock characters.
Shortcuts
Some tracks feature hidden shortcuts. When you see a route that veers from the usual path, it may lead to a shortcut.
Special abilities
Every driver has a unique ability that can be activated once per race. For example, Rez the starting driver, has the ability to boost leaving a trail of fire behind him that will slow down anyone in the way.
Tickets
A ticket is expended whenever you start a level. You can only hold a maximum of five tickets. To get a ticket back, earn a three star rank in a level. This requires finishing in first place on the race levels and besting the top time in time attack levels.
Unlimited tickets
Tickets regenerate over time after they are all consumed. To restore them instantly, advance the time on your device. Afterwards, set the time back to its correct value.
Upgrades
Upgrade your first car, the Beach Buggy, instead of spending your money on an entirely new vehicle. It has well balanced stats that can be upgraded well. When deciding on a specific vehicle upgrade, always consider Top Speed as your first choice.