The exclamation marks will indicate the direction where bombs will appear. You may need to follow a route that does not have as many coins or grind options to avoid bombs.
Bucks
Do not spend Bucks on continues or to skip missions. Save up for a Superbox instead, and use them only when you are going for a high score.
Coins
Collect the letters to form the bonus word to enter Skate mode. This is the easiest way to earn a lot of extra coins. Do not spend coins on boosts. Instead, save to purchase upgrades, board upgrades, the Gearbox, and new characters. You can watch the advertisements for free boosts.
Jumping
Use the double jump (triple jump if using a special character) to avoiding incoming missiles, get past obstacles, reach higher platforms, and collect coins for a streak.
Play as Mia
Connect to Facebook to unlock Mia. She has a grind bonus, 1 Superbox, and 10 Bucks. You will also start getting a daily bonus when connected to Facebook.
Power-ups
The Rocket power-up is very useful, as it will give you a short boost each time you get one. The Double Score and Shield are also useful. The Magnet is not usually needed, as you should have no trouble collecting coins. The Rainbow is the least power-up as you also should not have problems with your jumps. Keep upgrading your most used power-ups to increase their duration.
Scoring
Collect the Streak Bonus and Grind Bonus to boost your score. Collect all groups of coins and grind as much as possible after getting higher on the pipes.
Upgrades
Upgrade your board a few times in order to get a better score. You will get bonuses to your score each time you upgrade your board. It will make it easier to complete missions and gain ranks, which also increases your score.
Bombs...