Take your time on the first lap. Collect the 4 bananas at the top of the hill. Also get the 3 on the enbankment on the left. Take your time in the final lava area and collect 3 of the 4 bananas here. This should give you 10 bananas. Follow the strat above for laps 2 & 3 except ignore the part about collecting the bananas and instead follow the best racing line