Purchase items from the shop as soon as you can afford them. Consider getting the headphones to begin earning more coins, then the eye glasses to get the Platinum coin.
Scoring
Although your main goal is to get as many coins as possible, to begin scoring well you have to ignore coins and concentrate on the obstacles. You will get coins along the way, especially if you are using the power-ups and special items. Get as high up as possible to improve your score. Consider counting your taps to get into a rhythm in order to get higher. You will begin to anticipate the number of taps required to reach the next obstacle.
Speed
It will take some time for your family members to reach you. Take your time at first, the increase your pace while collecting as many coins as possible.