This SHOULD come as you play through world tour. Assuming you are collecting every star in every level. Please note that stars awarded for medals and bonus objectives DO NOT count towards this, it is only the ones throughout the courses.
There are 16 stars in each level and there are 20 levels. So there is a total of 320 stars to collect. There is also an achievement for 200, 300 of these stars, and getting all of them with silver medal for all courses. So I advise getting them all before advancing to the next level anyway while it is fresh in your memory.
You will require unlocking the split paths to get the majority of these stars. So I advise unlocking that before starting a level. Then what I done was on my first run, go through collecting all the stars (they are not too hard to find, look everywhere and backtrack) and do not worry about winning. You then get a feel for the course and I found it alot easier to win on my second run. If you miss any make sure you complete the level to save the stars, otherwise you will lose them. Also DO NOT skip forward using RB as this forfeits all the stars collected.
Feel free to comment below with suggestions to improving this guide ;)