For the first 600 miles:
Don't race the engine.
Don't maintain one constant speed, either slow or fast , for a long period of time.
Don't drive constantly at full-throttle or high rpm (over 7,000 rpm) for extended periods of time.
Avoid unnecessary hard stops.
Avoid full-throttle starts.
I use Pettit Racings Protek-R premix and am very happy with it. Many use the Idemitsu premix. Here is a video comparing the two. They are used at different recommended dilutions per gallon of gas, but due to the different price per ounce, it amazingly works out to the almost identical premix cost per tankful of gas.