How do you get a single star on mario kart wii?

Question

i stayed on track, in first place majority of the time, did tricks and used drift

Answer 1

you HAVE to get first place in every race of the circuit.  THEN, you have to get good times and beat the second place person by a considerable amount, maybe lik 5-10 seconds on short tracks and 10-15 seconds on longer tracks (just an estimate)