You achieve a star rank based on your "technique". That seems like a vague word, so let me do my best to elaborate.
Based on experience, getting first place on each track is a must for good "technique". Getting first place on each lap also seems to have a positive effect. But I think the most important factor is how fast each of your total track times are. You are more likely to get a star ranking if you are hit less, don't fall off the road, and stay on track more often.
It is possible to get first place on every track (earning a total score of 60) and not achieve a star ranking. It is also possible to get a star ranking without getting first place on each track.
With really good "technique", it is possible to get two and even three stars. YouTube is a good resource for research.
To summarize, the following is required to have a star ranking:
Get a final score of 52 or better.
Lead most of the laps.
Stay in first place for a good period of time.
Do a lot of tricks on ramps.
Avoid having to use Bullet Bills to catch up.
Use lots of techniques such as wheelies, avoiding POW Blocks, etc.
Do not fall off edges too much (one time is acceptable). If you get hit by many Spiny Shells and still win, this indicates that you are resistant and will probably have a high rank.
Do not get hit very many times by any item!
and:
A perfect 60 is required for a "Three Star" rank and a "Two Star" rank. A "One Star" rank is 58 to 60 all of these requirements. and you have to be in first.
Step 1. Record yourself getting a star rank in Mario Kart Wii. Step 2. Upload recording to Youtube.
In Mario Kart Wii you have to get a rank star or more on all of the 150cc grand prix cups
if you mean if a one star rank exists then yes
get at least 1 star rank
Get a 1 star rank or more in the 50cc wii cup
Get Star Rank In The Top Cups.
get star rank on the retro cups in 150cc
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mirrior cc:lighting cup star rank or higher
To get Bowser JR. in Mario Kart Wii, you need to have a "One Star" rank or better in all of the 100CC Retro Cups.
to earn baby daisy on Mario kart Wii you have to have star rank on all 50cc cups
get 2 stars or more on every cup